@article{article8d543c3c,
title   = {On the loss of regulatory for a class of weakly hyperbolic operators},
author = {Ebert, Marcelo Rempel and Kapp, R. A. and Santos Filho, José Ruidival dos},
year = {2009},
doi = {10.1016/j.jmaa.2009.05.026},
journal   = {Journal of Mathematical Analysis and Applications}
}