The MetaCyc database of metabolic pathways and enzymes and the BioCyc collection of pathway/genome databases

Ron Caspi, Richard Billington, Luciana Ferrer, Hartmut Foerster, Carol A. Fulcher, Ingrid M. Keseler, Anamika Kothari, Markus Krummenacker, Mario Latendresse, Lukas A. Mueller, Quang Ong, Suzanne Paley, Pallavi Subhraveti, Daniel S. Weave and Peter D. Karp.
Nucleic Acids Research. 2015 Published online 2 November 2015.