When every Gorenstein projective (resp. flat) module is strongly Gorenstein projective (resp. flat).

link: http://arxiv.org/abs/0909.2384
Abstract

In \cite{Ouarghi}, the authors discuss the rings over which all modules are
strongly Gorenstein projective. In this paper, we are interesting to an
extension of this idea. Thus, we discuss the rings over which every Gorenstein
projective (resp. flat) module is strongly Gorenstein projective (resp, flat).
Our aim is to give examples of rings with different Gorenstein global dimension
satisfied this condition.