Pravda, J. (1987). Activity of Czechoslovak geology and foreign countries. Czech Geological Office.
Chicago-Zitierstil (17. Ausg.)Pravda, Josef. Activity of Czechoslovak Geology and Foreign Countries. Prague: Czech Geological Office, 1987.
MLA-Zitierstil (9. Ausg.)Pravda, Josef. Activity of Czechoslovak Geology and Foreign Countries. Czech Geological Office, 1987.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.