Mitali Das

Last Updated: March 30, 2023

( To go to recent publications and working papers please follow this link.)

Ms. Das serves as an advisor in the Office of the Chief Economist of the IMF, providing intellectual input on issues of global economic significance and acting as the point of contact between the Office and government, international organizations, private sector and think tanks. Ms. Das is also Head of the IMF's Global Tail Risks work, tasked with identifying financial stability, geopolitical and social upheaval risks that may seep into risks to political and financial stability, and articulating mitigating actions to the Managing Director of the IMF. Her corporate service has extended to senior roles on the Diversity Reference Group and Gender Mainstreaming Strategy, both at the IMF, and on the selection committee of the American Association of University Women.

Prior to joining the IMF, Ms. Das held academic positions at Columbia University, Harvard University, Dartmouth College and the University of California Davis (2007-09). She has published widely on international finance, labor economics, open-economy macroeconomics, and inequality.

Ms. Das received her Ph.D. from the Massachusetts Institute of Technology (M.I.T).

Email: MDAS@imf.org

Education:

Ph.D in Economics, Massachusetts Institute of Technology (M.I.T), Cambridge Massachusetts

A.B. in Economics and International Relations, Mount Holyoke College, South Hadley MA, Summa cum laude


Other Professional Positions:

Assistant Professor of Economics (1998-2001), Associate Professor of Economics (2003-05), Columbia University, New York NY, 10027.

Postdoctoral Fellow, Harvard University, Institute of Quantitative Social Sciences, Cambridge MA, 2001 - 2002

Associate Professor of Economics, Dartmouth College, Hanover NH 03755 (2005 - 06)

Associate Professor of Economics, University of California, Davis CA 95616 (2007 - 09)


Work in progress:

"Central Banks as Dollar Lenders of Last Resort" , with Gita Gopinath, Taehoon Kim and Jeremy Stein, Working Paper, Harvard University, Cambridge MA. [pdf]

"Risk-off shocks and Preemptive Policies in Emerging Markets" with Gita Gopinath and Sebnem Kalemli-Ozcan. National Bureau of Economic Research (NBER), Cambridge MA. Working paper No. 29615 [html]

"A New Index of External Debt Sustainability" with Olivier Blanchard, NBER working paper No. 24068 [html]

"Macroeconomic Stability or Financial Stability: How are Capital Controls Used?", with Hailey Ordal, Journal of Financial Stability forthcoming.

IMF Books and Working Papers:

The Exposure to Routinization: Labor Market Implications for Developed and Developing Economies , Working Paper No. 18/135 , June 13, 2018

Why Is Labor Receiving a Smaller Share of Global Income? Theory and Empirical Evidence , Working Paper No. 17/169 , July 24, 2017

The External Balance Assessment (EBA) Methodology , Working Paper No. 13/272 , December 31, 2013

Chronicle of a Decline Foretold : Has China Reached the Lewis Turning Point? , Working Paper No. 13/26 , January 29, 2013

Other Published Materials

“Preemptive Policies and Risk-off shocks in Emerging Markets”, 2021, with Gita Gopinath and Sebnem Kalemli-Ozcan, NBER Working Paper 29615 [html]

“Central Banks as Dollar Lenders of Last Resort: Implications for Regulation and Reserves ”, with Gita Gopinath, Taehoon Kim and Jeremy Stein [html]

“Macroeconomic or Financial Stability: How are Capital Controls Used?”, with Haile Ordal, forthcoming Journal of Financial Stability [html]

"A New Framework for the Assessment of External Sustainability", with Olivier Blanchard, 2018, NBER Working Paper 24068 [html]

"The Term Structure of Uncovered Interest Parity in Emerging Markets”, Journal of Applied Economics , 2022, DOI: 10.1080/13504851.2022.2072464

"The Incidence of Capital Flow Management Measures: Evidence from a New Database”, with Mahir Binici and Evgenia Pugacheva. IMF Working Paper.                    

“Recalibration of Capital Controls: Evidence from the IMF Taxonomy”, with Mahir Binici,        Journal of International Money and Finance , 2021, 3, 1-31 . [html]

"Probabilistic Assessment of External Sustainability in Portugal”, Portuguese Economic Journal, 2021, [pdf]

“The Initial Impact of the Crisis on Emerging Market Countries”, with Olivier Blanchard, Faruqee, Brookings Papers on Economic Activity , Spring Volume, 2010, 263-323. [pdf]

"Estimation of Sample Selection Models”, with Whitney Newey and Francis Vella,                 Review of Economic Studies , 2003, Volume 70, 33-58, . [html]

“Income Inequality: The Aftermath of Stock Market Liberalization in Emerging Markets”,     Journal of Empirical Finance , Volume 10, 2003, 217-248, with S. Mohapatra. [html]

“Unemployment Dynamics During Recessions and Recoveries”, with R. Balakrishnan and P. Kannan, Crisis and Recovery , World Economic Outlook, 4/2010. [pdf]

“Instrumental Variables Estimators for Nonparametric Models with Discrete Endogenous Regressors”, Journal of Econometrics , 2004, Volume 124, 335-361. [html]

“External Positions and Rebalancing in the Euro Area”, 2014, 32, with Steven T. Phillips, The Third Pilot External Sector 2014 Report , IMF Policy Paper, Washington D.C. [pdf]

“What is a Safe Haven Currency?”, 2013, 15, with Steven T. Phillips, in The Pilot External Sector Report, IMF Policy Paper, Washington D.C. [pdf]

"The Exposure to Routinization: Labor Market Implications for Developed & Developing Economies”, Structural Change and Economic Dynamics, 2021, 90-113, with B. Hilgenstock. [html]

“Global Financial Conditions, Capital Flows and Reserve Accumulation”, 2015, with Steven T. Phillips, in External Sector Report 2015 , International Monetary Fund Policy Paper, IMF Washington D.C. [html]

“Worries over Unconventional Monetary Policies”, 2013, 15, Box 3, with Steven T. Phillips, in Pilot External Sector Report , IMF Policy Paper, Washington D.C. [pdf]

“The End of Cheap Labor”, Finance and Development , 2013, 50, 2-10, with Papa N’Diaye. [html]

“Simple Estimators for Nonparametric Panel Data Models with Sample Attrition”,                   Journal of Econometrics , 2003, Volume 120, 1, 159-180

“Why is Labor Receiving a Declining Share of Global Income?”, with M. Dao and Z. Koczan, Economic Policy , 2019, 34, 723–759 [html]

“When Are Large REER Shifts Followed by Large Current Account Movements?”, 2015, Box 5, 13-14, in 2015 External Sector Report , Policy Paper, IMF Washington D.C. [pdf]

“Estimation of a Panel Data Model with Insufficient Exclusion Restrictions”,                           Journal of Econometrics , 2001, Volume 114, 2, 297-328

“Functional Coefficient Instrumental Variables Models," with Z. Cai, H. Xiong and X.Wu,         Journal of Econometrics , 2006, 133, 207-241

“The Inter-generational link in Income Inequality: evidence from Adoptions”, with T. Sjogren, Economics Letters , 2001, 75, 55-60

"Rationales for the Use of Capital Flow Management since the Global Financial Crisis”, 2019, with E. Pugacheva in Macroeconomic Stabilization in the Digital Age , J. Beirne and G. Fernandez (eds.), Asian Development Bank, Tokyo, Japan.

“Routine Tasks, Automation, and Economic Dislocation around the World”, in Gaining Momentum , World Economic Outlook, 2018, Box 3.3, 48-51 (with Benjamin Hilgenstock). [pdf]

“How Has Asia Fared in the Age of Secular Stagnation?”, 2016, in Sustaining Economic Growth in Asia , Adam Posen, Jeremie Cohen and Thomas Helbing (editors), Peterson Institute of International Economies, Washington D.C.

"Semiparametric Analysis with Grouped Dependent Variables and Application to Physicians' Provision of Charity Care", Journal of Business and Economics Statistics , 2020, 26, 446-459

“Trade-related Policies for Inclusiveness”, Reinvigorating Trade and Inclusive Growth 2018, p 25-32, World Bank Group, Washington D.C. (with Paul Brenton). [pdf]

“Retreating from a Globalized World: Causes and Consequences of Indonesia’s Declining Engagement with the Global Economy”, 2018, in Realizing Indonesia’s Economic Potential L. Breuer, J. Guajardo, T. Kinda (editors), International Monetary Fund, Washington D.C.

"Capital Account Convertibility in the International Monetary System: A Timeline of Evolving Views and Measurements", Business and Economics , 2021, 12, 5, 4-19. [html]

"Prescriber Intent, Off-label Usage and the Early Discontinuation of Antidepressants”, with Jay Pomerantz, Ernst Berndt, S. Finkelstein et. al, Journal of Clinical Psychiatry , 2003, Volume 65(3), 395-404

“A Revised Approach for External Sustainability Assessment”, 2018, 36-40, in The EBA-Lite Methodology , Policy Paper, IMF Washington D.C. [html / pdf]

"My Policies or Yours- Have OECD Agricultural Policies Affected Incomes in Developing Countries?", 2007, comment in Globalization and Poverty , edited by Ann Harrison, University of Chicago Press.

"Has China Reached the Lewis Turning Point?" in China’s Economy in Transition: From External to Domestic Rebalancing , 2013, edited by A. Singh, P. N’Diaye and M. Nabar.

"Income Inequality: The Aftermath of Stock Market Liberalization in Emerging Markets", with S. Mohapatra, in Emerging Markets , 2002, Richard Roll (editor), International Library of Critical Writings.

"Chronicles of a Decline Foretold: China and the Lewis Turning Point”, with P. N'Diaye, International Monetary Fund, Washington D.C. [pdf]

“Malaysia: Past and Future Evolution”, 2014, in Malaysia and Its Economic Achievements A. Mourmouras and N. Sheridan (editors), International Monetary Fund, Washington D.C.

“The Role of Remittances and Aid in Low-Income Countries”, 2018, 9-12, in The Revised EBA-Lite Methodology , with C. Huang and M. Saleh, Policy Paper, IMF Washington D.C.

"Militarized Conflicts and the Saving-Investment Balance”, with C. Huang and M. Saleh, 2018, 16-18 in The Revised EBA-Lite Methodology , Policy Paper, IMF Washington D.C.

“Imbalances in Major Surplus Economies: Japan”, 2012, in Global Rebalancing: A Roadmap for Economic Recovery , Faruqee and Srinivasan (editors), International Monetary Fund, Washington D.C

“Imbalances in Major Deficit Economies: India”, 2012, in Global Rebalancing: A Roadmap for Economic Recovery , Faruqee and Srinivasan (editors), International Monetary Fund, Washington D.C

Blogs and Opinion Pieces

(1) PROJECT SYNDICATE : Emerging Markets’ Hidden Debt Risk , with S. Kalemli-Ozan, Liliana Varela, and D. Puy, May 2020. [html]

(2) VOXEU: Automation and Job Displacement in Emerging Markets, 2017 [html]

(3) VOXEU: Routinization, Globalization and the Fall in Labor’s Share of Income , 2018, [html]

(4) VOXEU: Technological Progress and Hollowing-out of the Middle-Skilled Labour Share of Income , 2020 [html]

G-20 Reports, Policy Papers and Country Reports

(1) “Toward an Integrated Policy Framework”, 2020, International Monetary Fund, Policy Paper No. 2020/046. [pdf]

(2) G-20 Surveillance Note, 2010, prepared for October 2010 Meeting of Finance Ministers and Central Bank Governors. [pdf]

(3) G-20 Surveillance Note, 2011, prepared for Paris, France February 2011 Meeting of Finance Ministers and Central Bank Governors. [pdf]

(4)G-20 Surveillance Note for the Meeting of Finance Ministers and Central Bank Governors: "Global Economic Prospects and Policy Challenges", April 2010, Washington D.C. [pdf]

(5) “The Revised External Balance Assessment Methodology EBA-Lite”, 2019, International Monetary Fund, Policy Paper No. 19/026. [pdf]

(6) “The External Adjustment in Portugal”, with Y. Korniyenko, September 2018, IMF Country Report No. 18/274, pages 66-76, IMF, Washington DC.
[pdf]

(7) “Understanding the Downward Trend in the Labor Share of Income”, 2017, World Economic Outlook, with M. Dao, Z. Koczan and W. Lian, IMF Washington DC.
[pdf]

(8) “2015 External Sector Report”, IMF Policy Paper, Presented to the Executive Board of the International Monetary Fund, Washington D.C.
[pdf]

(9) “Pilot 2014 External Sector Report”, IMF Policy Paper, presented to the Executive Board of the International Monetary Fund.
[pdf]

( To go to recent publications and working papers please follow this link.)

Ms. Das serves as an advisor in the Office of the Chief Economist of the IMF, providing intellectual input on issues of global economic significance and acting as the point of contact between the Office and government, international organizations, private sector and think tanks. Ms. Das is also Head of the IMF's Global Tail Risks work, tasked with identifying financial stability, geopolitical and social upheaval risks that may seep into risks to political and financial stability, and articulating mitigating actions to the Managing Director of the IMF. Her corporate service has extended to senior roles on the Diversity Reference Group and Gender Mainstreaming Strategy, both at the IMF, and on the selection committee of the American Association of University Women.

Prior to joining the IMF, Ms. Das held academic positions at Columbia University, Harvard University, Dartmouth College and the University of California Davis (2007-09). She has published widely on international finance, labor economics, open-economy macroeconomics, and inequality.

Ms. Das received her Ph.D. from the Massachusetts Institute of Technology (M.I.T).

Email: MDAS@imf.org

Education:

Ph.D in Economics, Massachusetts Institute of Technology (M.I.T), Cambridge Massachusetts

A.B. in Economics and International Relations, Mount Holyoke College, South Hadley MA, Summa cum laude


Other Professional Positions:

Assistant Professor of Economics (1998-2001), Associate Professor of Economics (2003-05), Columbia University, New York NY, 10027.

Postdoctoral Fellow, Harvard University, Institute of Quantitative Social Sciences, Cambridge MA, 2001 - 2002

Associate Professor of Economics, Dartmouth College, Hanover NH 03755 (2005 - 06)

Associate Professor of Economics, University of California, Davis CA 95616 (2007 - 09)


Work in progress:

"Central Banks as Dollar Lenders of Last Resort" , with Gita Gopinath, Taehoon Kim and Jeremy Stein, Working Paper, Harvard University, Cambridge MA. [pdf]

"Risk-off shocks and Preemptive Policies in Emerging Markets" with Gita Gopinath and Sebnem Kalemli-Ozcan. National Bureau of Economic Research (NBER), Cambridge MA. Working paper No. 29615 [html]

"A New Index of External Debt Sustainability" with Olivier Blanchard, NBER working paper No. 24068 [html]

"Macroeconomic Stability or Financial Stability: How are Capital Controls Used?", with Hailey Ordal, Journal of Financial Stability forthcoming.

IMF Books and Working Papers:

The Exposure to Routinization: Labor Market Implications for Developed and Developing Economies , Working Paper No. 18/135 , June 13, 2018

Why Is Labor Receiving a Smaller Share of Global Income? Theory and Empirical Evidence , Working Paper No. 17/169 , July 24, 2017

The External Balance Assessment (EBA) Methodology , Working Paper No. 13/272 , December 31, 2013

Chronicle of a Decline Foretold : Has China Reached the Lewis Turning Point? , Working Paper No. 13/26 , January 29, 2013

Other Published Materials

“Preemptive Policies and Risk-off shocks in Emerging Markets”, 2021, with Gita Gopinath and Sebnem Kalemli-Ozcan, NBER Working Paper 29615 [html]

“Central Banks as Dollar Lenders of Last Resort: Implications for Regulation and Reserves ”, with Gita Gopinath, Taehoon Kim and Jeremy Stein [html]

“Macroeconomic or Financial Stability: How are Capital Controls Used?”, with Haile Ordal, forthcoming Journal of Financial Stability [html]

"A New Framework for the Assessment of External Sustainability", with Olivier Blanchard, 2018, NBER Working Paper 24068 [html]

"The Term Structure of Uncovered Interest Parity in Emerging Markets”, Journal of Applied Economics , 2022, DOI: 10.1080/13504851.2022.2072464

"The Incidence of Capital Flow Management Measures: Evidence from a New Database”, with Mahir Binici and Evgenia Pugacheva. IMF Working Paper.                    

“Recalibration of Capital Controls: Evidence from the IMF Taxonomy”, with Mahir Binici,        Journal of International Money and Finance , 2021, 3, 1-31 . [html]

"Probabilistic Assessment of External Sustainability in Portugal”, Portuguese Economic Journal, 2021, [pdf]

“The Initial Impact of the Crisis on Emerging Market Countries”, with Olivier Blanchard, Faruqee, Brookings Papers on Economic Activity , Spring Volume, 2010, 263-323. [pdf]

"Estimation of Sample Selection Models”, with Whitney Newey and Francis Vella,                 Review of Economic Studies , 2003, Volume 70, 33-58, . [html]

“Income Inequality: The Aftermath of Stock Market Liberalization in Emerging Markets”,     Journal of Empirical Finance , Volume 10, 2003, 217-248, with S. Mohapatra. [html]

“Unemployment Dynamics During Recessions and Recoveries”, with R. Balakrishnan and P. Kannan, Crisis and Recovery , World Economic Outlook, 4/2010. [pdf]

“Instrumental Variables Estimators for Nonparametric Models with Discrete Endogenous Regressors”, Journal of Econometrics , 2004, Volume 124, 335-361. [html]

“External Positions and Rebalancing in the Euro Area”, 2014, 32, with Steven T. Phillips, The Third Pilot External Sector 2014 Report , IMF Policy Paper, Washington D.C. [pdf]

“What is a Safe Haven Currency?”, 2013, 15, with Steven T. Phillips, in The Pilot External Sector Report, IMF Policy Paper, Washington D.C. [pdf]

"The Exposure to Routinization: Labor Market Implications for Developed & Developing Economies”, Structural Change and Economic Dynamics, 2021, 90-113, with B. Hilgenstock. [html]

“Global Financial Conditions, Capital Flows and Reserve Accumulation”, 2015, with Steven T. Phillips, in External Sector Report 2015 , International Monetary Fund Policy Paper, IMF Washington D.C. [html]

“Worries over Unconventional Monetary Policies”, 2013, 15, Box 3, with Steven T. Phillips, in Pilot External Sector Report , IMF Policy Paper, Washington D.C. [pdf]

“The End of Cheap Labor”, Finance and Development , 2013, 50, 2-10, with Papa N’Diaye. [html]

“Simple Estimators for Nonparametric Panel Data Models with Sample Attrition”,                   Journal of Econometrics , 2003, Volume 120, 1, 159-180

“Why is Labor Receiving a Declining Share of Global Income?”, with M. Dao and Z. Koczan, Economic Policy , 2019, 34, 723–759 [html]

“When Are Large REER Shifts Followed by Large Current Account Movements?”, 2015, Box 5, 13-14, in 2015 External Sector Report , Policy Paper, IMF Washington D.C. [pdf]

“Estimation of a Panel Data Model with Insufficient Exclusion Restrictions”,                           Journal of Econometrics , 2001, Volume 114, 2, 297-328

“Functional Coefficient Instrumental Variables Models," with Z. Cai, H. Xiong and X.Wu,         Journal of Econometrics , 2006, 133, 207-241

“The Inter-generational link in Income Inequality: evidence from Adoptions”, with T. Sjogren, Economics Letters , 2001, 75, 55-60

"Rationales for the Use of Capital Flow Management since the Global Financial Crisis”, 2019, with E. Pugacheva in Macroeconomic Stabilization in the Digital Age , J. Beirne and G. Fernandez (eds.), Asian Development Bank, Tokyo, Japan.

“Routine Tasks, Automation, and Economic Dislocation around the World”, in Gaining Momentum , World Economic Outlook, 2018, Box 3.3, 48-51 (with Benjamin Hilgenstock). [pdf]

“How Has Asia Fared in the Age of Secular Stagnation?”, 2016, in Sustaining Economic Growth in Asia , Adam Posen, Jeremie Cohen and Thomas Helbing (editors), Peterson Institute of International Economies, Washington D.C.

"Semiparametric Analysis with Grouped Dependent Variables and Application to Physicians' Provision of Charity Care", Journal of Business and Economics Statistics , 2020, 26, 446-459

“Trade-related Policies for Inclusiveness”, Reinvigorating Trade and Inclusive Growth 2018, p 25-32, World Bank Group, Washington D.C. (with Paul Brenton). [pdf]

“Retreating from a Globalized World: Causes and Consequences of Indonesia’s Declining Engagement with the Global Economy”, 2018, in Realizing Indonesia’s Economic Potential L. Breuer, J. Guajardo, T. Kinda (editors), International Monetary Fund, Washington D.C.

"Capital Account Convertibility in the International Monetary System: A Timeline of Evolving Views and Measurements", Business and Economics , 2021, 12, 5, 4-19. [html]

"Prescriber Intent, Off-label Usage and the Early Discontinuation of Antidepressants”, with Jay Pomerantz, Ernst Berndt, S. Finkelstein et. al, Journal of Clinical Psychiatry , 2003, Volume 65(3), 395-404

“A Revised Approach for External Sustainability Assessment”, 2018, 36-40, in The EBA-Lite Methodology , Policy Paper, IMF Washington D.C. [html / pdf]

"My Policies or Yours- Have OECD Agricultural Policies Affected Incomes in Developing Countries?", 2007, comment in Globalization and Poverty , edited by Ann Harrison, University of Chicago Press.

"Has China Reached the Lewis Turning Point?" in China’s Economy in Transition: From External to Domestic Rebalancing , 2013, edited by A. Singh, P. N’Diaye and M. Nabar.

"Income Inequality: The Aftermath of Stock Market Liberalization in Emerging Markets", with S. Mohapatra, in Emerging Markets , 2002, Richard Roll (editor), International Library of Critical Writings.

"Chronicles of a Decline Foretold: China and the Lewis Turning Point”, with P. N'Diaye, International Monetary Fund, Washington D.C. [pdf]

“Malaysia: Past and Future Evolution”, 2014, in Malaysia and Its Economic Achievements A. Mourmouras and N. Sheridan (editors), International Monetary Fund, Washington D.C.

“The Role of Remittances and Aid in Low-Income Countries”, 2018, 9-12, in The Revised EBA-Lite Methodology , with C. Huang and M. Saleh, Policy Paper, IMF Washington D.C.

"Militarized Conflicts and the Saving-Investment Balance”, with C. Huang and M. Saleh, 2018, 16-18 in The Revised EBA-Lite Methodology , Policy Paper, IMF Washington D.C.

“Imbalances in Major Surplus Economies: Japan”, 2012, in Global Rebalancing: A Roadmap for Economic Recovery , Faruqee and Srinivasan (editors), International Monetary Fund, Washington D.C

“Imbalances in Major Deficit Economies: India”, 2012, in Global Rebalancing: A Roadmap for Economic Recovery , Faruqee and Srinivasan (editors), International Monetary Fund, Washington D.C

Blogs and Opinion Pieces

(1) PROJECT SYNDICATE : Emerging Markets’ Hidden Debt Risk , with S. Kalemli-Ozan, Liliana Varela, and D. Puy, May 2020. [html]

(2) VOXEU: Automation and Job Displacement in Emerging Markets, 2017 [html]

(3) VOXEU: Routinization, Globalization and the Fall in Labor’s Share of Income , 2018, [html]

(4) VOXEU: Technological Progress and Hollowing-out of the Middle-Skilled Labour Share of Income , 2020 [html]

G-20 Reports, Policy Papers and Country Reports

(1) “Toward an Integrated Policy Framework”, 2020, International Monetary Fund, Policy Paper No. 2020/046. [pdf]

(2) G-20 Surveillance Note, 2010, prepared for October 2010 Meeting of Finance Ministers and Central Bank Governors. [pdf]

(3) G-20 Surveillance Note, 2011, prepared for Paris, France February 2011 Meeting of Finance Ministers and Central Bank Governors. [pdf]

(4)G-20 Surveillance Note for the Meeting of Finance Ministers and Central Bank Governors: "Global Economic Prospects and Policy Challenges", April 2010, Washington D.C. [pdf]

(5) “The Revised External Balance Assessment Methodology EBA-Lite”, 2019, International Monetary Fund, Policy Paper No. 19/026. [pdf]

(6) “The External Adjustment in Portugal”, with Y. Korniyenko, September 2018, IMF Country Report No. 18/274, pages 66-76, IMF, Washington DC.
[pdf]

(7) “Understanding the Downward Trend in the Labor Share of Income”, 2017, World Economic Outlook, with M. Dao, Z. Koczan and W. Lian, IMF Washington DC.
[pdf]

(8) “2015 External Sector Report”, IMF Policy Paper, Presented to the Executive Board of the International Monetary Fund, Washington D.C.
[pdf]

(9) “Pilot 2014 External Sector Report”, IMF Policy Paper, presented to the Executive Board of the International Monetary Fund.
[pdf]