@article{CTGDC_1981__22_2_175_0,
     author = {Tholen, Walter and Wolff, Harvey},
     title = {Extensions of factorization systems},
     journal = {Cahiers de topologie et g\'eom\'etrie diff\'erentielle},
     pages = {175--190},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {22},
     number = {2},
     year = {1981},
     mrnumber = {649798},
     zbl = {0464.18002},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_1981__22_2_175_0/}
}