Band structure of δ-Sn and Ge-Sn alloys

C.H.L. Goodman contains statements which, if correct, would cast doubt upon much of the experimental work done prior to 1981 on a-Sn, the diamond lattice, semiconducting phase of tin. In this article, we review the evidence and argue that there already exists in the literature ample rebuttal of Goodman´s thesis.