@article{Stachowiak:2009,
author
=
"T.Stachowiak and M.Szydłowski and A.Maciejewski",
title
=
"Nonitegrability of density perturbations in the Friedmann-Robertson-Walker universe",
journal
=
"Journal of Mathematical Physics",
volume
=
"Vol. 47",
pages
=
"032502-1--032502-11",
year
=
"2006",
}