@article{1093891496, author = {Chapin, E. William}, title = {Set-valued set theory. I.}, journal = {Notre Dame J. Formal Logic}, volume = {15}, number = {1}, year = {1974}, pages = { 619-634}, language = {en}, url = {http://dml.mathdoc.fr/item/1093891496} }
Chapin, E. William. Set-valued set theory. I.. Notre Dame J. Formal Logic, Tome 15 (1974) no. 1, pp. 619-634. http://gdmltest.u-ga.fr/item/1093891496/