Não informado. (1979). Working paper series. International Potato Center, Social Science Department.
Chicago-viite (17. p.)Não informado. Working Paper Series. Lima: International Potato Center, Social Science Department, 1979.
MLA-viite (8. p.)Não informado. Working Paper Series. International Potato Center, Social Science Department, 1979.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.