1. PETRJOHN, B. G., J. R. SAuER, AND C. S. ROBBINS. 1995.Population trends from the North AmericanBreeding Bird Survey. Pages 3-39 in Ecology andmanagement of Neotropical migratory birds (T.E. Martin and D. M. Finch, Eds.). Oxford Uni-versity Press, New York.PetrjohnPopulation trends from the North American Breeding Bird Survey3Ecology and management of Neotropical migratory birds1995
2. Observer Differences in the North American Breeding Bird Survey