3 IZA Discussion Papers
IZA Discussion Paper No. 10376
IZA Discussion Paper No. 6234
发表于:美国农业》杂志上Economics, 2011, 93 (2), 505–511
IZA Discussion Paper No. 1965
发表于:美国农业》杂志上Economics, 2007, 89 (4), 852-863; excerpts also publishd in Economics Letters, 2008, 98 (1), 31-34
Typ