1. Automata on a 2-dimensional tape;Blum,1967
2. Two-characterizations of the context sensitive languages;Fisher,1969
3. On 2-dimensional pattern generating grammars;Yodogawa;IECE of Japan Trans. (C),1970
4. Some decision problems for two-dimensional nonwriting automata;Taniguchi;IECE of Japan Trans. (C),1971
5. Array automata and array grammars;Milgram,1971