1. Auslander, L., Shenefelt, M.: Fourier Transforms that Respect Crystallographic Symmetries. IBM J. Res. and Dev. 31, 213–223 (1987)
2. Elspas, B.: The Theory of Autonomous Linear Sequential Networks. In: Kautz, W. (ed.) Linear Sequential Switching Circuits, pp. 21–61. Holden-Day Inc. (1965)
3. Horn, R.A., Johnson, C.R.: Matrix Analysis. Cambridge University Press, Cambridge (1999)
4. McCoy, N.H.: Rings and Ideals. The Carus Mathematical Monographs. The Mathematical Association of America (1956)
5. Encyclopedia of Mathematics and its Applications;R. Lidl,1997