Gaya APA

Heckman, C, (. (1978). Georef Thesaurus and Guide to Indexing 2nd ed. . United States of America: American Geological Institute.

Gaya MLA

Heckman, Carol, (a.o.). "Georef Thesaurus and Guide to Indexing 2nd ed.". United States of America: American Geological Institute, 1978. Text.