@article{RISC3254,
author = {E.Shemyakova and F.Winkler},
title = {{Obstacles to the Factorization of Linear Partial Differential Operators into Several Factors}},
language = {english},
journal = {Programming and Computer Software},
volume = {33},
number = {2},
pages = {67--73},
isbn_issn = {ISSN 0361-7688},
year = {2007},
note = {Original version in Russian "Programmirovanie"},
refereed = {yes},
length = {7}
}