[1] W. Feller: An Introduction to Probability Theory and its Applications, Vol. I. J. Wiley & Sons -- Chapman & Hall, New York--London 1957 (Russian translation: Mir, Moscow 1964). MR 0088081

[2] F. Matúš: Axiomatizations of the notion of independence. -- private communication.

[3] J. Pearl: On the logic of probabilistic dependencies. TR 4/86, Cognitive Systems Laboratory, Dept. of Comp. Sci., Univ. of California, Los Angeles.

[4] J. R. Shoenfield: Mathematical Logic. Addision-Wesley Publ. Comp. 1967 (Russian translation: Nauka, Moscow 1975). MR 0225631 | Zbl 0155.01102

[5] M. Studený: Multiinformation and the problem of characterization of conditional independence relations. Problems Control Inform. Theory 19 (1989), No. 1 (to appear). MR 0986211

[6] J. Štěpán: Teorie pravděpodobnosti. (Probability Theory.) Academia, Praha 1987.