Hu, J., K. Yamada, and T. Sakanushi. “The Parameterization of All Disturbance Observers for Time-Delay Plants With Any Input and Output Disturbances”. ECTI Transactions on Computer and Information Technology (ECTI-CIT), vol. 8, no. 1, Apr. 2016, pp. 17-24, doi:10.37936/ecti-cit.201481.54384.