@article{1183532216,
author = {Neumann, Peter M.},
title = {The inequality of ${\text{SQPS}}$ and ${\text{QSP}}$ as operators on classes of groups},
journal = {Bull. Amer. Math. Soc.},
volume = {76},
number = {4},
year = {1970},
pages = { 1067-1069},
language = {en},
url = {http://dml.mathdoc.fr/item/1183532216}
}
Neumann, Peter M. The inequality of ${\text{SQPS}}$ and ${\text{QSP}}$ as operators on classes of groups. Bull. Amer. Math. Soc., Tome 76 (1970) no. 4, pp. 1067-1069. http://gdmltest.u-ga.fr/item/1183532216/