R. J.  Jensen, ?A preliminary numerical analysis of the red oak complex in Michigan and Wisconsin USA?, Taxon, vol. 26, pp. 399-407, 1977.

W. R.  Overlease, ?A study of the relationship between Scarlet Oak (Quercus coccinea Muenchh.) and Hill Oak (Quercus ellipsoidalis E.J. Hill) in Michigan and nearby states?, Journal of the Pennsylvania Academy of Science, vol. 51, pp. 47-50, 1977.

R. J.  Jensen, ?Numerical analysis of the scarlet oak complex (Quercus subgen. Erythrobalanus) in the eastern United states: relationships above the species level?, Systematic Botany, vol. 2, pp. 122-133, 1977.