Beltramo, A., and Hess, P. (1984). On the principal eigenvalue of a periodic parabolic operator.Comm. Part. Diff. Eqs. 9, 919–941.
Berestycki, H., and Lions, P. L. (1980).Some Applications of the Method of Super and Subsolutions, Lectures Notes in Mathematics, 782, Springer-Verlag, Berlin, pp. 16–41.
Bitterlin, M. (1992). Log-concavity of the periodic-parabolic eigenfunction.Diff. Int. Eqs. 5, 1041–1049.
Cantrell, R. S., and Cosner, C. (1989). Diffusive logistic equations with indefinite weights: Population models in disrupted environments.Proc. Roy. Soc. Edinburgh 112A, 293–318.
Coleman, B. D. (1979). Nonautonomous logistic equations as models of the adjustment of populations to environmental changes.Math. Biosci. 45, 139–173.
Dancer, E. N., and Hess, P. (1991). Behaviour of a semilinear periodic-parabolic problem when a parameter is small.Proc. Conf. Funct. Anal. Appl., Tokyo.
Furter, J. E., and López-Gómez, J. (1993). Diffusion mediated invasion problem for an heterogeneous Lotka-Volterra competition model. Preprint
Hess, P. (1991). Periodic-Parabolic Boundary Value Problems and Positivity, Pitman Research Notes in Mathematical Series 247, Essex.