On fractional PI λ controllers: Some tuning rules for robustness to plant uncertainties
Monje, C.A., A.J. Calderon, B.M. Vinagre, Y Chen, and V. Feliu. 2004. “On Fractional PI λ Controllers: Some Tuning Rules for Robustness to Plant Uncertainties”. Nonlinear Dynamics 38 (1-4): 369-81.