Paul Ehrlich, David Dobkin & Darryl Wheye, 1988.
“Cooperative Breeding” in The Birder's Handbook: A Field Guide to the Natural History of North American Birds Including All Species That Regularly Breed North of Mexico. Simon and Schuster, New York.
The essay is hosted on "Birds of Stanford" webpage. They provide an excellent summary of cooperative breeding including aspects from: Glen E. Woolfenden, John W. Fitzpatrick, 1984. The Florida Scrub Jay: Demography of a Cooperative-Breeding Bird. Princeton University Press, N. J., USA. 406pp.
Look under "Essays" and click the link for "Alphabetical order" to find "Cooperative Breeding".