Prebiotic Porphyrin Genesis: Porphyrins from Electric Discharge in Methane, Ammonia, and Water Vapor Hodgson, G. W. ; Ponnamperuma, Cyril Abstract Publication: Proceedings of the National Academy of Science Pub Date: January 1968 DOI: 10.1073/pnas.59.1.22 Bibcode: 1968PNAS...59...22H