%0 Journal Article %A Janusz Mierczy/nski %T The principal spectrum for linear nonautonomous parabolic PDEs of second order: Space-independent case %J Colloquium Mathematicum %D 2001 %P 95-100 %V 90 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm90-1-8/ %R 10.4064/cm90-1-8 %G en %F 10_4064_cm90_1_8