@article{AIHPA_1996__65_3_273_0,
     author = {Banach, Zbigniew and Piekarski, S{\l}awomir},
     title = {An {almost-Robertson-Walker} universe model and the equivalence classes of perturbations : nonbarotropic perfect fluids},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {273--309},
     publisher = {Gauthier-Villars},
     volume = {65},
     number = {3},
     year = {1996},
     zbl = {0865.53088},
     language = {en},
     url = {http://www.numdam.org/item/AIHPA_1996__65_3_273_0/}
}