@article{1255380829,
author = {Feller, William},
title = {On the intrinsic form for second order differential operators},
journal = {Illinois J. Math.},
volume = {2},
number = {1},
year = {1958},
pages = { 1-18},
language = {en},
url = {http://dml.mathdoc.fr/item/1255380829}
}
Feller, William. On the intrinsic form for second order differential operators. Illinois J. Math., Tome 2 (1958) no. 1, pp. 1-18. http://gdmltest.u-ga.fr/item/1255380829/