Response to letter written by: P. Cruz, J.C. Santos, F.D. Magalhaes, A. Mendes to "Comparison of finite difference and control volume methods for solving differential equations, by G.G. Botte, J.A. Ritter, R.E. White, 24 (2000) 2633-2654". - Gerardine G. Botte; James A. Ritter; Ralph E. White (Comput. Chem. Eng., 2005)