File:Parker, J.D., Rissing, S.W. 2002. Molecular evidence for the origin of workerless social parasites in the ant genus Pogonomyrmex.pdf

Summary
Parker, J.D., Rissing, S.W. 2002. Molecular evidence for the origin of workerless social parasites in the ant genus Pogonomyrmex. Evolution 56: 2017-2028.