@article{1077491743, author = {Whittemore, James K.}, title = {Bertrand curves and helices}, journal = {Duke Math. J.}, volume = {6}, number = {1}, year = {1940}, pages = { 235-245}, language = {en}, url = {http://dml.mathdoc.fr/item/1077491743} }
Whittemore, James K. Bertrand curves and helices. Duke Math. J., Tome 6 (1940) no. 1, pp. 235-245. http://gdmltest.u-ga.fr/item/1077491743/