J.  Weickert and Schnörr, C., ?Variational Optic Flow Computation with a Spatio-Temporal Smoothness Constraint?, J. Math. Imaging and Vision, vol. 14, pp. 245?255, 2001.

C.  Schnörr and Weickert, J., ?Variational Image Motion Computation: Theoretical Framework, Problems and Perspectives?, in Mustererkennung 2000, Kiel, Germany, 2000.