A. M.  Baumgartner, ?Ruby-throated Hummingbird populations in northeastern Oklahoma-1977-1978?, North American Bird Bander, vol. 14, pp. 115-117, 1989.

A. M.  Baumgartner, ?Composition of Ruby-throated Hummingbird populations in northeast Oklahoma?, Bulletin of the Oaklahoma Ornithological Society, vol. 22, pp. 3-5, 1989.