Incoming Resources
- Garrard Pub. Co., Champaign, Ill., 1971
- Illinois Natural History Survey, Champaign, Ill., 2001
- Garrard Pub. Co., Champaign, Ill., 1969
- Garrard Pub. Co., Champaign, Ill., c1978
- Illinois Natural History Survey, Champaign, Ill., 2002
- SP, L.L.C., Champaign, Ill., c2001
- Garrard Pub. Co., Champaign, Ill., c1979