1. Forbes, G.F., Digital Differential Analyzers, Copyright Forbes (1957)
2. Sizer. T.R., The Digital Differential Analyzer, Chapman a. Hall (1968)
3. Leonhard, W., Archiv f. Electrotechn., 49, 215–234 (1964)
4. Michaelis, H., Regelungstechnik, 10, 114–118 u. 337–343 (1963)
5. Mitchel, J.M., IRE Nat. Conv. Rec., 6, Prt. 4, 206–216 (1958)