John F. Cyranski Necessary and sufficient conditions to solve the rate distortion problem for general alphabets. [Citation Graph (0, 0)][DBLP] Inf. Sci., 1981, v:24, n:3, pp:217-227 [Journal]
Paavo Turakainen On nonstochastic languages and homomorphic images of stochastic languages. [Citation Graph (0, 0)][DBLP] Inf. Sci., 1981, v:24, n:3, pp:229-253 [Journal]