@article{104820, author = {Milo\v s R\'ab}, title = {Asymptotic formulas for solutions of the equation $[p(t)y']'=q(t)y+r(t)$}, journal = {Archivum Mathematicum}, volume = {010}, year = {1974}, pages = {79-85}, zbl = {0318.34062}, mrnumber = {0382795}, language = {en}, url = {http://dml.mathdoc.fr/item/104820} }
Ráb, Miloš. Asymptotic formulas for solutions of the equation $[p(t)y']'=q(t)y+r(t)$. Archivum Mathematicum, Tome 010 (1974) pp. 79-85. http://gdmltest.u-ga.fr/item/104820/
Asymptotic expansions of solutions of the equation $[p(x)y']' - q(x)y = 0$ with complex-valued coefficients, Arch. Math. (Brno), 8 (1972) No 1, 1-15. (1972) | MR 0315231