@article{1103033800, author = {Isbell, J. R.}, title = {Natural sums and abelianizing.}, journal = {Pacific J. Math.}, volume = {14}, number = {4}, year = {1964}, pages = { 1265-1281}, language = {en}, url = {http://dml.mathdoc.fr/item/1103033800} }
Isbell, J. R. Natural sums and abelianizing.. Pacific J. Math., Tome 14 (1964) no. 4, pp. 1265-1281. http://gdmltest.u-ga.fr/item/1103033800/