In this paper, we shall present two new nonlinear variation of parameters formulae for the summary difference equations in several independent variables. A corrected variation of parameters formula for the corresponding integrodifferential equation is also provided. Some applications that dwell upon the importance of these new results are also included. © 1994.
Sheng, Q., & Agarwal, R. P. (1994). Nonlinear variation of parameter methods for summary difference equations in several independent variables. Applied Mathematics and Computation, 61(1), 39–60. https://doi.org/10.1016/0096-3003(94)90145-7