On simple singular gp - injective modules

We investigate von Neumann regularity of rings whose simple singular right R-modules are GP-injective. It is proved that a ring; R is strongly regular iff R is a weakly right duo ring whose simple singular right R-modules are GP-injective. And it is also shown that R is either a strongly right bounded ring or a zero insertive ring in which every simple singular right R-module is GP-injective are reduced weakly regular rings. Several known results are unified and extended.