@article{GDZPPN002203278,
title = {On the reduction of the Poincar\'e rank of singular systems of ordinary differential equations.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {372},
year = {1986},
pages = {80-96},
zbl = {0569.34037},
url = {http://dml.mathdoc.fr/item/GDZPPN002203278}
}
Schäfke, R.; Volkmer, H. On the reduction of the Poincaré rank of singular systems of ordinary differential equations.. Journal für die reine und angewandte Mathematik, Tome 372 (1986) pp. 80-96. http://gdmltest.u-ga.fr/item/GDZPPN002203278/