@article{01413887,
title = {Equivalence of holonomic differential equations.},
journal = {Lobachevskii Journal of Mathematics},
volume = {3},
year = {1999},
pages = {39-71},
zbl = {0937.37051},
language = {en},
url = {http://dml.mathdoc.fr/item/01413887}
}
Doubrov, B.; Komrakov, B.; Morimoto, T. Equivalence of holonomic differential equations.. Lobachevskii Journal of Mathematics, Tome 3 (1999) pp. 39-71. http://gdmltest.u-ga.fr/item/01413887/