Selected peer-reviewed research articles
2023
Babadjanova, Mashkhura; Bobojonov, Ihtiyor; Bekchanov, Maksud; Kuhn, Lena; Glauben, Thomas (2023) Can domestic wheat farming meet the climate change-induced challenges of national food security in Uzbekistan?. International Journal of Water Resources Development [in press].
Djuraeva, Mukhayyo; Bobojonov, Ihtiyor; Kuhn, Lena; Glauben, Thomas (2023) The impact of agricultural extension type and form on technical efficiency under transition: An empirical assessment of wheat production in Uzbekistan. Economic Analysis and Policy 77: 203-221.
Eltazarov, Sarvarbek; Bobojonov, Ihtiyor; Kuhn, Lena; Glauben, Thomas (2023) Improving risk reduction potential of weather index insurance by spatially downscaling gridded climate data - a machine learning approach. Big Earth Data [in press].
Eltazarov, Sarvarbek; Bobojonov, Ihtiyor; Kuhn, Lena; Glauben, Thomas (2023)The role of crop classification in detecting wheat yield variation for index-based agricultural insurance in arid and semiarid environments. Journal of Environmental and Sustainability Indicators [in press].
Emileva, Begaiym; Kuhn, Lena; Bobojonov, Ihtiyor; Glauben, Thomas (2023) The role of smartphone-based weather information acquisition on climate change perception accuracy: Cross-country evidence from Kyrgyzstan, Mongolia and Uzbekistan. Climate Risk Management 41
Moritz, Laura; Kuhn, Lena; Bobojonov, Ihtiyor (2023) The role of peer imitation in agricultural index insurance adoption: Findings from lab-in-the-field experiments in Kyrgyzstan. Review of Development Economics [in press]
Tadjiev, Abdusame; Djanibekov, Nodir, Herzfeld, Thomas (2023) Does zero tillage save or increase production costs? Evidence from smallholders in Kyrgyzstan. International Journal of Agricultural Sustainability 21 (1), 2270191.
2022
Amirova, Iroda; Petrick, Martin; Djanibekov, Nodir (2022) Investment traps and resilience to shocks: An experimental study of Central Asian collective water governance. Irrigation and Drainage
Babakholov, Sherzod; Bobojonov, Ihtiyor; Hasanov, Shavkat; Glauben, Thomas (2022) An empirical assessment of the interactive impacts of irrigation and climate on farm productivity in Samarkand region, Uzbekistan. Environmental Challenges 7: 100502.
Peña Guerrero, Mayra Daniela; Umirbekov, Atabek; Tarasova, Larisa; Müller, Daniel (2022) Comparing the performance of high-resolution global precipitation products across topographic and climatic gradients of Central Asia. International Journal of Climatology.
Pomfret, Richard; Djanibekov, Nodir (2022) 30 years of farm restructuring and water management reforms in Central Asia. Central Asian Journal of Water Research 8 (1): 49-56.
Rufin, P., M. D. Peña-Guerrero, A. Umirbekov, Y. Wei & D. Müller (2022) Post-Soviet changes in cropping practices in the irrigated drylands of the Aral Sea basin. Environmental Research Letters, 17, 095013.
Tleubayev, Alisher; Bobojonov, Ihtiyor; Götz, Linde (2022) Agricultural policies and technical efficiency of wheat production in Kazakhstan and Russia: Evidence from a stochastic frontier approach. Journal of Agricultural and Applied Economics.
Umirbekov, A., M. D. Peña-Guerrero & D. Müller (2022) Regionalization of climate teleconnections across Central Asian mountains improves the predictability of seasonal precipitation. Environmental Research Letters, 17, 055002.
2021
Akhmadiyeva, Zarema; Herzfeld, Thomas (2021) How does practice matches land laws in Central Asia? Land Use Policy 109.
Bobojonov, Ihtiyor (2021) Bioeconomic Models. Oxford Research Encyclopedia of Environmental Science: Oxford University Press.
Chezhia, Giorgi; Perekhozhuk, Oleksandr; Glauben, Thomas (2021) Measuring oligopsonistic market power in the Kazakh grain processing industry: Empirical evidence from the General Identification Method. Journal of New Economy 22 (3): 6–27.
Didovets, Iulii; Lobanova, Anastasia; Krysanova, Valentina; Menz, Christoph; Babagalieva, Zhanna; Nurbatsina, Aliya; Gavrilenko, Nadejda; Khamidov, Vohid; Umirbekov, Atabek; Qodirov, Sobir; Muhyyew, Dowletgeldi; Hattermann, Fred Fokko (2021) Central Asian rivers under climate change: Impacts assessment in eight representative catchments. Journal of Hydrology: Regional Studies 34, 100779.
Dufhues, Thomas; Möllers, Judith; Traikova, Diana; Buchenrieder, Gertrud; Runschke, David (2021) Why villagers stay put – A structural equation model on staying intentions. Journal of Rural Studies 81: 345-357.
Egamberdiev, Bekhzod (2021) Household impact of the COVID-19 pandemic from a development economics perspective: A review. Regional Science Inquiry 13 (1): 15-30.
Eltazarov, Sarvarbek; Bobojonov, Ihtiyor; Kuhn, Lena; Glauben, Thomas (2021) Mapping weather risk – A multi-indicator analysis of satellite-based weather data for agricultural index insurance development in semi-arid and arid zones of Central Asia. Climate Services 23. 100251.
Hajdu, Anna; Gagalyuk, Taras; Bukin, Eduard; Petrick, Martin (2021) Determinants of corporate social responsibility among farms in Russia and Kazakhstan: A multilevel approach using survey data. International Food and Agribusiness Management Review 24 (4): 697-716.
Kuhn, Lena; Bobojonov, Ihtiyor (2021) The role of risk rationing in rural credit demand and uptake: lessons from Kyrgyzstan. Agricultural Finance Review.
Kvartiuk, Vasyl; Petrick, Martin (2021) Liberal land reform in Kazakhstan? The effect on land rental and credit markets. World Development 138, 105285.
Lobanova, Anastasia; Didovets, Iulii; Menz, Christoph; Umirbekov, Atabek; Babagalieva, Zhanna; Hattermann, Fred; Krysanova, Valentina (2021) Rapid assessment of climate risks for irrigated agriculture in two river basins in the Aral Sea Basin. Agricultural Water Management 243, 106381.
Lombardozzi, Lorena; Djanibekov, Nodir (2021) Can self-sufficiency policy improve food security? An inter-temporal assessment of the wheat value-chain in Uzbekistan. Eurasian Geography and Economics 62 (1): 1-20.
Robinson, Sarah; Bozayeva, Janil; Mukhamedova, Nozilakhon; Djanibekov, Nodir; Petrick, Martin (2021) Ranchers or pastoralists? Farm size, specialisation and production strategy amongst cattle farmers in south-eastern Kazakhstan. Pastoralism 11:31.
Rolinski, Susanne; Prishchepov, Alexander; Guggenberger, Georg; Bischoff, Norbert; Kurganova, Irina; Schierhorn, Florian; Müller, Daniel; Müller, Christoph (2021) Dynamics of soil organic carbon in the steppes of Russia and Kazakhstan under past and future climate and land use. Regional Environmental Change 21 (3).
2020
- Schierhorn, Florian; Hofmann, Max; Adrian, Inken; Bobojonov, Ihtiyor; Müller, Daniel (2020) Spatially varying impacts of climate change on wheat and barley yields in Kazakhstan. Journal of Arid Environments 178, 104164.
- Wuepper, David; Borrelli, Pasquale; Mueller, Daniel; Finger, Robert (2020) Quantifying the soil erosion legacy of the Soviet Union. Agricultural Systems 185, 102940.
- Buchenrieder, Gertrud; Dufhues, Thomas; Möllers, Judith; Runschke, David; Sagyndykova, Galiya (2020) Return to the countryside: The return intentions of highly educated young people in the Akmola province of northern Kazakhstan. Population, Space and Place 26 (2): 1-14.
- Dufhues, Thomas; Buchenrieder, Gertrud; Sun, Zhanli (2020) Exploring Policy Options in Regulating Rural–Urban Migration with a Bayesian Network: A Case Study in Kazakhstan. European Journal of Development Research
2019
- Akhmadiyeva, Zarema; Abdullaev, Iskandar (2019) Water management paradigm shifts in the Caspian Sea region: Review and outlook. Journal of Hydrology 568: 997-1006.
- Amirova, Iroda; Petrick, Martin; Djanibekov, Nodir (2019) Long- and short-term determinants of water user cooperation: Experimental evidence from Central Asia. World Development 113: 10-25.
- Baumann, Matthias; Kamp, Johannes; Pötzschner, Florian; Bleyhl, Benjamin; Dara, Andrey; Hankerson, Brett; Prishchepov, Alexander V.; Schierhorn, Florian; Müller, Daniel; Hölzel, Norbert; Krämer, Roland; Urazaliyev, Ruslan; Kuemmerle, Tobias (2019) Declining human pressure and opportunities for rewilding in the steppes of Eurasia. Diversity and Distributions 26(9), 1058-1070.
- Dara et al. (2019) Post-Soviet Land-Use Change Affected Fire Regimes on the Eurasian Steppes. Ecosystems 2019: 1-14.
- Hankerson, Florian; Schierhorn, Florian; Prishchepov, Alexander V.; Dong, Changxing; Eisfelder, Christina; Müller, Daniel (2019) Modeling the spatial distribution of grazing intensity in Kazakhstan. PLoS ONE 14(1): e0210051.
- Krivonos, Ekaterina; Kuhn, Lena (2019) Trade and dietary diversity in Eastern Europe and Central Asia. Food Policy 88
- Mukhamedova, Nozilakhon; Pomfret, Richard (2019) Why does sharecropping survive? Agrarian institutions and contract choice in Kazakhstan and Uzbekistan. Comparative Economic Studies 61 (4): 576-597.
- Petrick, Martin; Götz, Linde (2019) Herd Growth, Farm Organisation and Subsidies in the Dairy Sector of Russia and Kazakhstan. Journal of Agricultural Economics 70 (3): 789-811.
- Prishchepov et al. (2019) Revealing the determinants of wheat yields in the Siberian breadbasket of Russia with Bayesian networks. Land Use Policy 80: 21-31.
- Svanidze, Miranda; Götz, Linde; Duric, Ivan; Glauben, Thomas(2019) Food security and the functioning of wheat markets in Eurasia: A comparative price transmission analysis for the countries of Central Asia and the South Caucasus. Food Security 11(3): 733-752.
- Svanidze, Miranda;Götz, Linde(2019)Spatial market efficiency of grain markets in Russia: Implications of high trade costs for export potential. Global Food Security 21: 60-68.
- Svanidze, Miranda; Götz, Linde (2019) Determinants of spatial market efficiency of grain markets in Russia. Food Policy 89: 101769.
2018
- Dara, A.; Baumann, M.; Kuemmerle, T.; Pflugmacher, D.; Rabe, A.; Griffiths, P.; Hölzel N.; Kamp, J.; Freitag, M.; Hostert, P. (2018) Mapping the timing of cropland abandonment and recultivation in northern Kazakhstan using annual Landsat time series. Remote Sensing of Environment 213: 49-60.
- Djanibekov, Utkur; Van Assche, Kristof; Boezeman, Daan; Villamor, Grace B.; Djanibekov, Nodir (2018) A coevolutionary perspective on the adoption of sustainable land use practices: The case of afforestation on degraded croplands in Uzbekistan. Journal of Rural Studies 59: 1-9.
- Klümper, Frederike; Theesfeld, Insa; Herzfeld, Thomas (2018) Discrepancies between paper and practice in policy implementation: Tajikistan's property rights and customary claims to land and water. Land Use Policy 75: 327-339.
- Mukhamedova, Nozilakhon; Wegerich, Kai (2018) The feminization of agriculture in post-Soviet Tajikistan. Journal of Rural Studies 57: 128–139.
- Mukhamedova, Nozilakhon (2018) Frauen als Wassermeister? Arbeitsmigration und Feminisierung der Landwirtschaft in Tadschikistan und Usbekistan. Zentralasien-Analysen (124): 2-5.
- Soliev, Ilkhom; Wegerich, Kai; Akramova, Indira; Mukhamedova, Nozilakhon (2018) Balancing the Discussion of Benefit Sharing in Transboundary Water Governance: Stressing the Long-Term Costs in an Empirical Example from Central Asia. International Journal of Water Governance 6: 19-42
- Swinnen, J.; Burkitbayeva, S.; Schierhorn, F.; Prishchepov. Alexander S.; Mueller, Daniel (2018) Production potential in the “bread baskets” of Eastern Europe and Central Asia. Global Food Security 14: 38-53.
2017
Bobojonov, Ihtiyor; Djanibekov, Nodir; Voigt, Peter (2017) Future perspectives on regional and international food security: Emerging players in the region: Uzbekistan. In: Gomez y Paloma, S., Mary, S., Langrell, S., Ciaian, P. (eds.): The Eurasian Wheat Belt and Food Security. Global and Regional Aspects, 195-213: Springer.
- Chatalova, Lioudmila; Djanibekov, Nodir; Gagalyuk, Taras; Valentinov, Vladislav (2017) The Paradox of Water Management Projects in Central Asia: An Institutionalist Perspective. Water 9 (4): 1-14.
- Klümper, Frederike; Herzfeld, Thomas; Theesfeld, Insa (2017) Can Water Abundance Compensate for Weak Water Governance? Determining and Comparing Dimensions of Irrigation Water Security in Tajikistan. Water 9 (4): 1-20.
- Klümper, Frederike; Theesfeld, Insa (2017) The Land–Water–Food Nexus: Expanding the Social–Ecological System Framework to Link Land and Water Governance. Resources 6 (3): 1-16.
- Mukhamedova, Nozilakhon; Wegerich, Kai (2017) The rising challenge of multiple water resource use at the urban fringes – evidence from Ferghana District of Uzbekistan. Central Asian Journal of Water Research 3 (2): 41-53.
- Petrick, Martin; Oshakbayev, Dauren; Taitukova, Regina; Djanibekov, Nodir (2017) The return of the regulator: Kazakhstan's cotton sector reforms since independence. Central Asian Survey 36 (4): 430-452.
- Petrick, Martin (2017) Incentive provision to farm workers in post-socialist settings: evidence from East Germany and North Kazakhstan. International Food and Agribusiness Management Review 20 (2): 239-256.
- Swinnen, Johan; Burkitbayeva, Saule; Schierhorn, Florian; Prishchepov, Alexander; Müller, Daniel (2017) Production Potential in the "Bread Baskets" of Eastern Europe and Central Asia. Global Food Security 14: 38-53.
2016
- Bobojonov, Ihtiyor; Berg, Ernst; Franz-Vasdeki, Jennifer; Martius, Christopher; Lamers, John P.A. (2016) Income and irrigation water use efficiency under climate change: An application of spatial stochastic crop and water allocation model to Western Uzbekistan. Climate Risk Management (13): 19-30.
- Bobojonov, Ihtiyor; Teuber, Ramona; Hasanov, Shavkat; Urutyan, Vardan; Glauben, Thomas (2016) Farmers’ export market participation decisions in transition economies: a comparative study between Armenia and Uzbekistan. Development Studies Research 3 (1): 25-35.
- Burkitbayeva, Saule; Qaim, Matin; Swinnen, Johan (2016) A Black (White) Hole in the Global Spread of GM Cotton Trends in Biotechnology 34 (4): 260-263.
- Djanibekov, Nodir; Van Assche, Kristof; Valentinov, Vladislav (2016) Water governance in Central Asia: A Luhmannian perspective. Society & Natural Resources 29 (7): 822-835.
- Reddy, J. Mohan; Jumaboev, Kahramon; Bobojonov, Ihtiyor; Carli, Carlo; Eshmuratov, Davron (2016) Yield and water use efficiency of potato varieties under different soil-moisture stress conditions in the Fergana Valley of Central Asia. Agroecology and Sustainable Food Systems 40 (5): 407-431
- Wegerich, Kai; Soliev, Ilkhom; Akramova, Indira (2016) Dynamics of water reallocation and cost implications in the transboundary setting of Ferghana Province. Central Asian Survey 35 (1): 38-60.
Contributions to anthologies
- Bobojonov, Ihtiyor; Berg, Ernst; Franz-Vasdeki, Jennifer; Martius, Christopher; Lamers, John P.A. (2016) Income and irrigation water use efficiency under climate change: An application of spatial stochastic crop and water allocation model to Western Uzbekistan. Climate Risk Management (13): 19-30.
Akramkhanov, Akmal; Djanibekov, Utkur; Nishanov, Nariman; Djanibekov, Nodir; Kassam, Shinan N. (2018) Barriers to sustainable land management in Greater Central Asia: With special reference to five former Soviet republics. In: Squires, V. R., Qi, L. (eds.): Sustainable Land Management in Greater Central Asia: An Integrated and Regional Perspective: Routledge.
Bekchanov, Maksud; Djanibekov, Nodir; Lamers, John P.A. (2018) Water in Greater Central Asia: A cross-cutting management issue. In: Squires, V. R., Qi, L. (eds.): Sustainable Land Management in Greater Central Asia: An Integrated and Regional Perspective: Routledge.
Bobojonov, Ihtiyor; Djanibekov, Nodir; Voigt, Peter (2017) Future perspectives on regional and international food security: Emerging players in the region: Uzbekistan. In: Gomez y Paloma, S., Mary, S., Langrell, S., Ciaian, P. (eds.): The Eurasian Wheat Belt and Food Security. Global and Regional Aspects, 195-213: Springer.
Götz, Linde; Duric, Ivan (2018) Do export restrictions reduce domestic price volatility? Evidence from the wheat export controls in Kazakhstan, Russia and Ukraine. In: Pfaffenzeller, S. (ed.): Global Commodity Markets and Development Economics, Routledge Studies in Development Economics, 115-128: Routledge.
Articles (non-peer-reviewed)
IAMO Discussion Papers
Tadjiev, Abdusame; Kurbanov, Zafar; Djanibekov, Nodir; Govind, Ajit; Akramkhanov, Akmal (2023) Determinants and impact of farmers' participation in social media groups: Evidence from irrigated areas of Kazakhstan and Uzbekistan. IAMO Discussion Paper No. 201, Halle (Saale): IAMO.
Amirova, Iroda, Petrick, Martin, Djanibekov, Nodir (2022) Community, state and market: Understanding historical water governance evolution in Central Asia. IAMO Discussion Paper No. 200, Halle (Saale): IAMO.
Djanibekov, Nodir; Herzfeld, Thomas (2022) The impact of COVID-19 on agrifood systems and rural areas in Central Asia and Caucasus countries: Final report of a study commissioned by FAO. IAMO Discussion Paper No. 198, Halle (Saale): IAMO.
Akhmadiyeva, Zarema; Herzfeld, Thomas (2021) The reality of land rights in Kazakhstan and Uzbekistan. IAMO Annual 23: 9-16.
Djanibekov, Nodir; Charyyeva, Suray; Sanaev, Golib (2020) Cotton sector reforms in Central Asia. IAMO Annual 22: 46-54.
- Bobojonov, Ihtiyor; Kuhn, Lena; Moritz, Laura; Eltazarov, Sarvarbek; Glauben, Thomas (2019) Improving climate resilience through agricultural insurance – the KlimALEZ project. IAMO Jahreszahl 21: 27-35.
- Krivonos, Ekaterina; Kuhn, Lena (2019) Trade and dietary diversity in Eastern Europe and Central Asia. IAMO Discussion Paper No. 182, Halle (Saale): IAMO.
- Svanidze, Miranda; Götz, Linde; Duric, Ivan; Glauben, Thomas (2019) Food security and the functioning of wheat markets in Eurasia: A comparative price transmission analysis for the countries of Central Asia and the South Caucasus. IAMO Discussion Paper No. 183, Halle (Saale): IAMO.
- Ganiev, Ibragim; Sanaev, Golib; Pardaev, Khusniddin (2018) Career expectations of undergraduate and graduate students at agricultural universities in Uzbekistan. IAMO Discussion Paper No. 179, Halle (Saale): IAMO.
- Hasanov, Shavkat; Sanaev, Golib (2018) Non-farm employment trends and policy in rural areas of Samarkand region (Uzbekistan). IAMO Discussion Paper No. 176, Halle (Saale): IAMO.
- Oshakbayev, Dauren; Taitukova, Regina; Petrick, Martin; Djanibekov, Nodir (2018) Kazakhstan's cotton sector reforms since independence. IAMO Discussion Paper No. 172, Halle (Saale): IAMO.
- Ganiev, Ibragim; Djanibekov, Nodir; Hasanov, Shavkat; Petrick, Martin (2017) The state of doctoral research in Uzbekistan: Results of a survey of doctoral students in agricultural economics. IAMO Discussion Paper No. 164, Halle (Saale): IAMO.
- Tleubayev, Alisher; Bobojonov, Ihtiyor; Götz, Linde; Hockmann, Heinrich; Glauben, Thomas (2017) Determinants of productivity and efficiency of wheat production in Kazakhstan: A Stochastic Frontier Approach. IAMO Discussion Paper No. 160, Halle (Saale), Germany: IAMO.
Bobojonov, Ihtiyor; Teuber, Ramona; Hasanov, Shavkat; Urutyan, Vardan; Glauben, Thomas (2017) Does the Russian import ban on Western foodstuffs improve the export prospects of farmers from the Caucasus and Central Asia? The findings from a survey of farmers. IAMO Jahreszahl 19: 19-31.
Djanibekov, Nodir; Petrick, Martin (2017) Models of crop diversification in Central Asia. IAMO Jahreszahl 19: 33-43.
Hankerson, Brett; Schierhorn, Florian; Müller, Daniel (2017) Pasture use and livestock production in Kazakhstan. IAMO Jahreszahl 19: 45-54.
Petrick, Martin; Djanibekov, Nodir (2016) Obstacles to crop diversification and cotton harvest mechanisation: Farm survey evidence from two contrasting districts in Uzbekistan. IAMO Discussion Paper No. 153, Halle (Saale): IAMO.
IAMO Policy Briefs
Akhmadiyeva, Zarema; Herzfeld, Thomas (2020) How to align formal land rights with farmers’ perceptions in Central Asia?. IAMO Policy Brief No. 38, Halle (Saale).
Akhmadiyeva, Zarema; Herzfeld, Thomas (2020) Как согласовать формальные права на землю с реальными представлениями фермеров о землепользовании в Центральной Азии?. IAMO Policy Brief No. 38, Halle (Saale).
Djanibekov, Nodir; Kurbanov, Zafar; Tadjiev, Abdusame; Govind, Ajit; Akramkhanov, Akmal (2023) Farmers' social media groups for better extension and advisory services. IAMO Policy Brief No. 46, Halle (Saale).
Djanibekov, Nodir; Herzfeld, Thomas; Arias, Pedro Marcelo (2021) Food policy measures in response to COVID-19 in Central Asia and the Caucasus: Taking stock after the first year of the pandemic. IAMO Policy Brief No. 43, Halle (Saale).
Djanibekov, Nodir; Herzfeld, Thomas; Arias, Pedro Marcelo (2021) Меры продовольственной политики в условиях COVID-19 в Центральной Азии и на Кавказе: Подведение итогов первого года пандемии. IAMO Policy Brief No. 43, Halle (Saale).
Kuhn, Lena; Bobojonov, Ihtiyor; Glauben, Thomas (2018) Landwirtschaft in Zeiten der Dürre: Wie Digitalisierung ein nachhaltiges Risikomanagement unterstützen kann. IAMO Policy Brief No. 35, Halle (Saale).
Petrick, Martin; Djanibekov, Nodir (2019) Farm restructuring in Uzbekistan: What next?IAMO Policy Brief No. 36, Halle (Saale).
Petrick, Martin; Djanibekov, Nodir (2019) Ўзбекистонда фермер хўжаликлари реструктуризацияси: Истиқболдаги вазифалар. IAMO Policy Brief No. 36, Halle (Saale).
Petrick, Martin; Djanibekov, Nodir (2019) Реструктуризация фермерских хозяйств в Узбекистане: Дальнейшие действия. IAMO Policy Brief No. 36, Halle (Saale).
Others
Djanibekov, Nodir; Petrick, Martin (2020) Statistical data on farming structures, land use and agricultural output for provinces in five Central Asian countries 1992-2015 (Version: 1.0.0). SowiDataNet|datorium.
Rufin, P., M. D. Peña-Guerrero, A. Umirbekov, Y. Wei & D. Müller (2022) Landsat-based maps of cropping practices in the irrigated drylands of the Aral Sea Basin (1987-2019).
Zorya, Sergiy; Djanibekov, Nodir; Petrick, Martin (2019) Farm restructuring in Uzbekistan: How did it go and what is next? World Bank Working Papers, Washington, D.C..
- Zorya, Sergiy; Djanibekov, Nodir; Petrick, Martin (2019) Реструктуризация хозяйств в Узбекистане: Ее реализация и дальнейшие действия. World Bank Working Papers, Washington, D.C..