Institute For Scientific Co-operation. (1980). Economics. Laupp & Gobel, Tubingen.
Lua i Stíl Chicago (17ú heag.)Institute For Scientific Co-operation. Economics. Federal Republic of Germany: Laupp & Gobel, Tubingen, 1980.
Lua MLA (9ú heag.)Institute For Scientific Co-operation. Economics. Laupp & Gobel, Tubingen, 1980.