364 BELL SYSTEM TECHNICAL JOURNAL 



References 



1. S. A. Schelkunoff, Solution of linear and slightly nonlinear equations, Quart. A pp. Math.f 



vol.3, p. 348, Jan., 1946. 



2. J. Liouville, Memoires sur le developpement des fonctions ou parties de fonctions en 



series dont les divers termes sont assujetis a satisfaire a une meme equation differen- 

 tieile du second ordre, contenant un parametre variable,//, de Math: Pureset Appl.y 

 V. i, p. 253-265, 1836, v. 2, p. 16-35 and p. 418-436, 1837. A brief discussion of 

 the method will be found in "Numerical studies in differential equations" by H. 

 Levy and E. A. Baggott, London, 1934; but these authors apply it to the numerical 

 solution of non-linear equations and do not seem to have appreciated that its real 

 potentiaUties lie in the field of linear equations, where they use only the better known 

 methods. 



3. Thornton C. Fry, The use of the integraph in the practical solution of differential 



equations by Picard's method of successive approximations, Proc. Int. Math. Con- 

 gress of Toronto, pp. 405-428, 1924. 



