R. E. ’ Dell, James, J. J., and Richards, J. H.,
“Congeneric Serpentine and Nonserpentine Shrubs Differ More in Leaf Ca:Mg than in Tolerance of Low N, Low P, or Heavy Metals”,
Plant and Soil, vol. 2803012910615254324512117621221607148506416045594413791470436412741071573097134167215862, no. 1-2Suppl., pp. 49 - 64, 2006.
C. Scott Cooper, Hyder, D. Nelson, Petersen, R. G., and Sneva, F. A.,
“The Constituent Differential Method of Estimating Species Composition in Mixed Hay1”,
Agronomy Journal, vol. 49, no. 4, p. 190, 1957.