1. The Mayaro Tarballs; Manmade or Natural?;Amoco Trinidad Oil Company,1980
2. A survey of stranded tar on Trinidad beaches 1980–81;Georges,1982
3. Naturally Occurring Hydrocarbon Seeps in the Gulf of Mexico and the Caribbean Sea,1979
4. Naturally occurring hydrocarbons in the Gulf of Mexico and the Caribbean;Geyer,1981