1989-November 1994 Robbins, C. S., J. R. Sauer, R. S. Greenberg, and S. Droege.
Population declines in North American birds that migrate to the neotropics.
Robbins, C. S., S. Droege, and J. R. Sauer. Monitoring bird populations with Breeding Bird Survey and atlas data. Titus, K., M. R. Fuller, D. W. Stauffer, and J. R. Sauer. Pages 53-64 in Northeast Raptor Management Symposium and Workshop, Nat. Droege, S., and J. R. Sauer 1989.