@article{01108913, title = {Operator }, journal = {Electronic Research Announcements of the American Mathematical Society [electronic only]}, volume = {3}, year = {1997}, pages = {131-142}, doi = {10.1090/S1079-6762-97-00038-3}, zbl = {0888.46046}, language = {en}, url = {http://dml.mathdoc.fr/item/01108913} }
Higson, Nigel; Kasparov, Gennadi. Operator . Electronic Research Announcements of the American Mathematical Society [electronic only], Tome 3 (1997) pp. 131-142. doi : 10.1090/S1079-6762-97-00038-3. http://gdmltest.u-ga.fr/item/01108913/