Evaluation of the response of nonlinear systems to asymptotically almost periodic inputs. - Irwin W. Sandberg; Gideon J. J. Van Zyl (ISCAS (3), 2001)

Harmonic balance and almost periodic inputs. - Irwin W. Sandberg; Gideon J. J. Van Zyl (ISCAS (1), 2002)

A novel frequency-domain small-signal analysis of resonant power converters. - Gideon J. J. Van Zyl (IEEE Trans. Circuits Syst. I Regul. Pap., 2004)