Cathcart, James B. 1917- Phosphate rock in Colombia : a preliminary report / By James B. Cathcart and Francisco Zambrano O. -- Washington : United States Government Printing Office, 1969 - 77 p. + 1 plan. pleg. -- (Geological Survey Bulletin ; 1272-A). Subjects--Topical Terms: Fosfatos - Colombia Universal Decimal Class. No.: 549.752/.757(861)