Nonlinearity quantification for the optimal state feedback controller. - Tobias Schweickhardt; Frank Allgöwer; Frank J. Doyle III (ECC, 2003)

Linear modeling error and steady-state behaviour of nonlinear dynamical systems. - Tobias Schweickhardt; Frank Allgöwer (CDC/ECC, 2005)

On System Gains, Nonlinearity Measures, and Linear Models for Nonlinear Systems. - Tobias Schweickhardt; Frank Allgöwer (IEEE Trans. Autom. Control., 2009)