The generalized matrix product and its applications. - Gerhard X. Ritter; Huixia Zhu (J. Math. Imaging Vis., 1992)

The generalized matrix product and the wavelet transform. - Huixia Zhu; Gerhard X. Ritter (J. Math. Imaging Vis., 1993)

The p-Product and Its Applications in Signal Processing. - Huixia Zhu; Gerhard X. Ritter (SIAM J. Matrix Anal. Appl., 1995)