@article{GDZPPN002479516,
title = {On the Solutions of (ry')' + qy = f.},
journal = {Monatshefte f\"ur Mathematik},
volume = {79},
year = {1975},
pages = {115-118},
zbl = {0323.34029},
url = {http://dml.mathdoc.fr/item/GDZPPN002479516}
}
Krall, Allan M. On the Solutions of (ry')' + qy = f.. Monatshefte für Mathematik, Tome 79 (1975) pp. 115-118. http://gdmltest.u-ga.fr/item/GDZPPN002479516/