1. Proc. Lond. Math. Soc., Vol. XXVIII, pp. 357?366.
2. The method of setting up the abstract form of a given concrete group by use of a rectangular table of the latter has been successfully employed by the writer in recent articles in theProc. Lond. Math. Soc., andTrans. Amer. Math. Soc.
3. Band 51, pp. 417?444; particularly pp. 435?6.
4. For references to the literature on this theorem, seeAnnalen, Bd. 51, p. 419.
5. Annalen, Bd. 51, p. 435.