@article{02218617, title = {Extensions of racks and quandles.}, journal = {Homology, Homotopy and Applications}, volume = {7}, year = {2005}, pages = {151-167}, zbl = {1077.18010}, language = {en}, url = {http://dml.mathdoc.fr/item/02218617} }
Jackson, Nicholas. Extensions of racks and quandles.. Homology, Homotopy and Applications, Tome 7 (2005) pp. 151-167. http://gdmltest.u-ga.fr/item/02218617/