1. On the infinite zero module and infinite pole module;Conte,1984
2. Algebraic structure of linear dynamical systems 1. The module of ε;Kalman,1965
3. Topics in Mathematical System Theory;Kalman,1969
4. T. Kailath, Linear Systems (Prentice Hall, Englewood Cliffs, NJ) Ch. 6.
5. Some notes on valuation theory in linear systems;Kung,1978