  Some binary matrices like (1,-1) and (1,0) were studied by many authors like
Cohn, Wang, Ehlich and Ehlich and Zeller, and Mohan, Kageyama, Lee, and Gao. In
this recent paper by Mohan et al considered the M-matrices of Type I and II by
studying some of their properties and applications. In the present paper they
discussed the M-matrices of Type III, and studied their properties and
applications. They gave some constructions of SPBIB designs and some
corresponding M-graphs, which are being constructed by it. This is the
continuation of our earlier research work in this direction, and these papers
establish the importance of non-orthogonal matrices as well.
