@article{1102905686, author = {Mahowald, Mark}, title = {The index of a tangent $2$-field.}, journal = {Pacific J. Math.}, volume = {61}, number = {2}, year = {1975}, pages = { 539-548}, language = {en}, url = {http://dml.mathdoc.fr/item/1102905686} }
Mahowald, Mark. The index of a tangent $2$-field.. Pacific J. Math., Tome 61 (1975) no. 2, pp. 539-548. http://gdmltest.u-ga.fr/item/1102905686/