Christodoulakis, Helias, Kevrekidis, Kevrekidis, Papadopoulos, Abdullaev, and Konotop. 2005. “ON 3+1 DIMENSIONAL FRIEDMAN-ROBERTSON-WALKER UNIVERSES WITH MATTER”. In Nonlinear Waves: Classical and Quantum Aspects, 153:135-43. Dordrecht: Springer.