Forest trees of Illinois :
how to know them : a pocket manual describing their most important characteristics /
by Wilbur R. Mattoon and R.B. Miller, in cooperation with the Forest Service, United States Dept. of Agriculture.
APA Citation
Mattoon, W. R. (Wilbur Reed)., Miller, R. B. (Robert Barclay)., Illinois. Dept. of Conservation. (1933). Forest trees of Illinois: how to know them : a pocket manual describing their most important characteristics. 7th ed. Springfield, [Ill.]: State of Illinois, Dept. of Conservation.
MLA Citation
Mattoon, Wilbur R. (Wilbur Reed), 1875-1941, R. B. (Robert Barclay) Miller, and Illinois. Dept. of Conservation. Forest Trees of Illinois: How to Know Them : a Pocket Manual Describing Their Most Important Characteristics. 7th ed. Springfield, [Ill.]: State of Illinois, Dept. of Conservation, 1933.
Warning: These citations may not always be complete (especially for serials).