@article{GDZPPN002231573, title = {Hereditary endomorphism monoids of projective acts.}, journal = {Manuscripta mathematica}, volume = {70}, year = {1991}, pages = {133-144}, zbl = {0722.20049}, url = {http://dml.mathdoc.fr/item/GDZPPN002231573} }
Knauer, Ulrich; Normak, Peter. Hereditary endomorphism monoids of projective acts.. Manuscripta mathematica, Tome 70 (1991) pp. 133-144. http://gdmltest.u-ga.fr/item/GDZPPN002231573/