  In this article we corrected the trilinear formula for triple disjoint matrix
multiplication given in the article 'J. Laderman, V. Pan, X. H. Sha, On
practical Algorithms for Accelerated Matrix Multiplication, Linear Algebra and
its Applications. Vol. 162-164 (1992) pp. 557-588', which is incorrect for
matrix dimensions equal to two or greater. That formula is a base of two
algorithms, for disjoint and single matrix multiplication. The necessary
correction made the amount of non scalar products raise, slightly increasing
the algorithm time complexity. We also corrected explicit formulas, in the
bilinear form, for triple disjoint matrix multiplication. They are explicit,
thus convenient for practical use of fast matrix multiplication algorithms in
question.
