1. A.N. Kolmogorov, “Three Approaches to the Concept of the Amount of Information,” Problemy Peredachi Informatsii, 1, (1965), pp. 3–11.
2. A.K. Zhvonkin and L.A. Levin, “The Complexity of Finite Objects and the Development of the Concepts of Information and Randomness by Means of the Theory of Algorithms,” Russian Mathematical Surveys 25, (1970), pp. 83–124.
3. C.P. Schnorr, “A Unified Approach to the Definition of Random Sequences,” Math. Systems Theory, 5, No. 3, (1971), pp. 246–258.
4. R.J. Solomonoff, “A Formal Theory of Inductive Inference, Part I,” Information and Control, 7, (1964), pp. 1–22.
5. R.J. Solomonoff, “A Formal Theory of Inductive Inference, Part II,” Information and Control, 7, (1964), pp. 224–254.