1. Adams, E. W.: 1959, ?The Foundation of Rigid Body Mechanics and the Derivation of its Laws from those of Particle Mechanics?, in L. Henkin, P. Suppes and A. Tarski (eds.), The Axiomatic Method, North-Holland Publ. Comp., Amsterdam.
2. Balzer, W. and Sneed, J. D.: 1977, ?Generalized Net Structures of Empirical Theories, I?, Studia Logica 36, 195?211.
3. Balzer, W. and Sneed, J. D.: 1978, ?Generalized Net Structures of Empirical Theories, II?, Studia Logica 27, 167?194.
4. Carnap, R.: 1958, Introduction to Symbolic Logic and its Applications, Dover, New York.
5. Hartkämper, A. and Schmidt, H.-J. (eds.): 1981, Structure and Approximation in Physical Theories, Plenum Pr., New York/London.