@article{10_4153_CJM_1986_026_3,
     author = {Jr., K. D. Magill and Misra, P. R. and Tewari, U. B.},
     title = {Epimorphisms {From} {S(X)} onto {S(Y)}},
     journal = {Canadian journal of mathematics},
     pages = {538--551},
     year = {1986},
     volume = {38},
     number = {3},
     doi = {10.4153/CJM-1986-026-3},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1986-026-3/}
}