| 其他書名 | A Progress Report to the Economic Research Service of the United States Dept. of Agriculture, Under Contract No. 12-17-0017-52, Project No. 11252-21 |
| 出版 | Department of Agricultural Economics, Michigan State University and Departamento de Economía y Ciencias Sociales, Facultad de Agronomía e Instituto Forestal, Universidad Nacional de Colombia, 1962 |
| URL | http://books.google.com.hk/books?id=ZZBMAAAAMAAJ&hl=&source=gbs_api |