In this paper, we propose a novel approach to describe and analyze circuits which consist of any linear circuit connected to an arbitrary number of memristors. Due to the memristors the whole circuit is a nonlinear system. We use a Volterra series approach to derive solutions of voltages and currents in memristive circuits. Thereby, the memristors are presented by polynomial functions which cover a broad class of devices. It will be shown that the different order Volterra kernels depend on the one hand on the structure and parameters of the linear part of the circuit-represented by the admittance or impedance matrix-and on the other hand on the coefficients in the polynomial memristor representation. We consider this approach to be an important step in the development of memristive network theory.