1. W. J. Eckert, Punched Card Methods in Scientific Computation, The Thomas J. Watson Astronomical Computing Bureau, 1940, chap. x.
2. Multiplication of matrices;Alt, Franz L.;Math. Tables Aids Comput.,1946
3. W. J. Eckert, op. cit., chap. xi.
4. Automatic integration of linear sixth-order differential equations by means of punched-card machines;Hausman, L. F.;Rev. Sci. Instruments,1947