Rings characterized by injectivity classes

Recently, there are a number of well known theorems which characterize rings in terms of injective modules (cf. [2], [3], [5] and [8]). The purpose of this paper is to give general theorems which show that some similar results remain true when many other classes of general injective modules are considered in place of injective modules. Our results encompass several well known results by Huynh and Smith, Liu, and Xue. In particular we answer negatively the question of Yue Chi Ming [11] and an example is given to show that E-injective modules form an intermediate class between continuous and quasi-continuous modules(cf. Example 3).