Não informado. (1970). Geodex Retrieval System for Geotechnical Abstracts. Geodex International.
Chicago (17e ed.) BronvermeldingNão informado. Geodex Retrieval System for Geotechnical Abstracts. Sonoma, Calif: Geodex International, 1970.
MLA (8e ed.) BronvermeldingNão informado. Geodex Retrieval System for Geotechnical Abstracts. Geodex International, 1970.
Let op: Deze citaties zijn niet altijd 100% accuraat.