It has been known for years that sub-integrated elements are more efficient and accurate than the fully integrated elements. For conventional formulation of constrained problems, reduced integration is even a necessity for removal of lockings. Unfortunately, the spurious mechanisms of the sub-integrated elements may give rise to singular assembled stiffness matrices and thus plague practical engineering analyses. Even if the spurious mechanisms are suppressed by the displacement boundary conditions, unexpected oscillations of the predicted field quantities may be observed. In the past decades, a large amount of effort has been spent on developing stabilization scheme for sub-integrated elements. In this paper, a brief review would be given on stabilization. A special version of hybrid stabilization based on the admissible matrix formulation would be presented. Sample elements and their numerical examples are given.