@article{CM_1987__61_3_353_0, author = {Hilton, Peter and Roitberg, Joseph}, title = {Relative epimorphisms and monomorphisms in homotopy theory}, journal = {Compositio Mathematica}, pages = {353--367}, publisher = {Martinus Nijhoff Publishers}, volume = {61}, number = {3}, year = {1987}, zbl = {0624.55005}, mrnumber = {883488}, language = {en}, url = {http://www.numdam.org/item/CM_1987__61_3_353_0/} }