Jaffee, D. (1998). Levels of socio-economic development theory (2nd ed.). Praeger.
Lua i Stíl Chicago (17ú heag.)Jaffee, David. Levels of Socio-economic Development Theory. 2nd ed. Westport, Conn: Praeger, 1998.
Lua MLA (9ú heag.)Jaffee, David. Levels of Socio-economic Development Theory. 2nd ed. Praeger, 1998.
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