[1] Václav Dupač: O Kiefer - Wolfowitzově aproximační metodě. Časopis pro pěst. mat. 82 (1957), 1, 47-75. (Appeared in Selected Translations in Mathematical Statistics and Probability.) MR 0089556
[2] R. A. Howard: Dynamic Programming and Markov Processes. J. Wiley, New York 1960. MR 0118514 | Zbl 0091.16001