Billings, W. D., and A. F. Mark. "Factors Involved in the Persistence of Montane Treeless Balds." Ecology 38, no. 1 (1957): 140-142.

Oosting, H. J., and W. D. Billings. "A Comparison of Virgin Spruce-Fir Forest in the Northern and Southern Appalachian System." Ecology 32, no. 1 (1951): 84-103.

Billings, W. D., and William B. Drew. "Bark Factors Affecting the Distribution of Corticolous Bryophytic Communities." The American Midland Naturalist 20, no. 2 (1938): 302-330.

Billings, W. D., Stanley A. Cain, and William B. Drew. "Winter Key to the Trees of Eastern Tennessee." The Journal of the Southern Appalachian Botanical Club 2, no. 3 (1937): 29-44.