@article{GDZPPN002344327,
title = {On maximal symmetrie ordinary differential operators},
journal = {Mathematica Scandinavica},
volume = {4},
year = {1956},
pages = {22-28},
zbl = {0074.06702},
url = {http://dml.mathdoc.fr/item/GDZPPN002344327}
}
CODDINGTON, EARL A. On maximal symmetrie ordinary differential operators. Mathematica Scandinavica, Tome 4 (1956) pp. 22-28. http://gdmltest.u-ga.fr/item/GDZPPN002344327/