Greenfieldia

Boucot, A. J.; Alvarez, F.; Leibold, A. (1997). The jugum and salinity tolerance of <i>Greenfieldia</i> (Brachiopoda: Late Silurian). <em>Journal of Paleontology.</em> 71(1): 156-157.

Grabau, A. W.; Sherzer, W. H. (1910). The Monroe formation of southern Michigan and adjoining regions. <em>Michigan Geological and Biological Survey, Publication 2 [Geological Series 1].</em> 1-248, 32 pls.

Treatise on Invertebrate Paleontology. (1997-2007). Part H revised, Brachiopoda. <em>Geological Society of America, Boulder; and University of Kansas Press, Lawrence,.</em> vol. 1-6.