Kvenvolden, Keith A. (2006). "Organic geochemistry – A retrospective of its first 70 years". Organic Geochemistry. Cilt 37. ss. 1-11. doi:10.1016/j.orggeochem.2005.09.001.
Treibs, A.E. (1936). "Chlorophyll- und Häminderivate in organischen Mineralstoffen". Angewandte Chemie. Cilt 49. ss. 682-686. doi:10.1002/ange.19360493803.
