@article{05904715,
title = {Helmholtz conditions and their generalizations.},
journal = {Balkan Journal of Geometry and its Applications (BJGA)},
volume = {15},
year = {2010},
pages = {80-89},
zbl = {1227.49042},
language = {en},
url = {http://dml.mathdoc.fr/item/05904715}
}
Krupková, Olga; Malíková, Radka. Helmholtz conditions and their generalizations.. Balkan Journal of Geometry and its Applications (BJGA), Tome 15 (2010) pp. 80-89. http://gdmltest.u-ga.fr/item/05904715/