Product integration in reflexive Banach spaces

LetX denote a reflexive Banach space and {A(t)|t0,T]} a time dependent family of accretive operators defined onX. Conditions are placed on {A(t)|t0,T]} which are sufficient to guarantee the existence of solutions to the Cauchy initial value problem:u(t,x)+A(t)u(t,x)=0; u(0,x)=x. These solutions are obtained via the method of product integration; however limits for the infinite product are taken with respect to the weak topology.