Variational principles and the effect of a cutoff on population pattern sizeV. Méndez, W. Horsthemke, J. Casas-Vázquez and E. P. ZemskovEur. Phys. J. Special Topics, 146 (2007) 189-197DOI: https://doi.org/10.1140/epjst/e2007-00179-6