@article{10_4153_CMB_1993_032_0,
     author = {Nicholson, W. K.},
     title = {On {PP-Endomorphism} {Rings}},
     journal = {Canadian mathematical bulletin},
     pages = {227--230},
     year = {1993},
     volume = {36},
     number = {2},
     doi = {10.4153/CMB-1993-032-0},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1993-032-0/}
}