@article{1183536255, author = {Zettl, Anton}, title = {A constructive characterization of disconjugacy}, journal = {Bull. Amer. Math. Soc.}, volume = {81}, number = {4}, year = {1975}, pages = { 145-147}, language = {en}, url = {http://dml.mathdoc.fr/item/1183536255} }
Zettl, Anton. A constructive characterization of disconjugacy. Bull. Amer. Math. Soc., Tome 81 (1975) no. 4, pp. 145-147. http://gdmltest.u-ga.fr/item/1183536255/