@article{700210,
title = {Asymptotic formulas for the solutions of the equation (py')' + qy = 0},
booktitle = {Differential Equations and Their Applications},
series = {GDML\_Books},
publisher = {Slovensk\'e pedagogick\'e nakladate\v lstvo},
address = {Bratislava},
year = {1967},
pages = {217-220},
zbl = {0185.15902},
url = {http://dml.mathdoc.fr/item/700210}
}
Ráb, M. Asymptotic formulas for the solutions of the equation (py')' + qy = 0, dans Differential Equations and Their Applications, GDML_Books, (1967), pp. 217-220. http://gdmltest.u-ga.fr/item/700210/