Thomas Cluzeau Evelyne Hubert Resolvent Representation for Regular Differential Ideals. 395-425 2003 13 Appl. Algebra Eng. Commun. Comput. 5 http://dx.doi.org/10.1007/s00200-002-0110-4 db/journals/aaecc/aaecc13.html#CluzeauH03