Cohen, A. N. 1998. Biological invasions in the San Francisco Estuary. In Marine and Aquatic Nonindigenous Species in California: An Assessment of Current Status and Research Needs. Olin, P. G., Cassell, J. L., Eds.. Marine and Aquatic Nonindigenous Species in California: An Assessment of Current Status and Research Needs. California Sea Grant College System, University of California: La Jolla, CA. pp 7-8.