[1] GRUSKA J.: 
Some classifications of context-free languages. Information and Control 14, 1969, 152-179. 
MR 0253836 | 
Zbl 0174.28901[2] HERMAN G. T., ROZENBERG G.: 
Developmental Systems and Languages. North 
Zbl 0306.68045[3] KELEMENOVÁ A.: Frequency of a letter occurence in words of Lindenmayer systems. To appear in Acta Fac. RN UC.
[4] KELEMENOVÁ A.: Algorithms in biology. Proc. of ALGORITMY '81, published by JSMF, Bratislava, 1981, 134-140 (in Slovak).
[5] KELEMENOVÁ A.: 
Gramatical levels of the position restricted grammars. In Proc. of MFCS '81, Lecture Notes in Computer Science 118, Springer-Verlag, Berlin, 1981, 347-359. 
MR 0652768[6] LINDENMAYER A.: Mathematical models of cellular interactions in development I, II. Journal of Theoretical Biology 18, 1968, 280-299, 300-315.
[7] LINDENMAYER A., ROZENBERG G. (eds.): 
Automata, Languages, Development. North-Holland, Amsterdam, 1976. 
MR 0451874 | 
Zbl 0346.92001[8] ROZENBERG G., SALOMAA A. (eds.): 
L-systems. Lecture Notes in Computer science 15, Springer-Verlag, Berlin, 1974. 
MR 0398141 | 
Zbl 0281.00016[9] ROZENBERG G., SALOMAA A.: 
The Mathematical Theory of L-systems. Academic Press, New York, 1980. 
MR 0561711 | 
Zbl 0508.68031[10] SALOMAA A., SOITTOLA M.: 
Automata-Theoretic Aspects of Formal Power Series. Springer-Verlag, New York, 1978. 
MR 0483721 | 
Zbl 0377.68039[11] VITÁNYI P. M. B.: 
Lindenmayer systems: Structure, languages and growth functions. PhD thesis, Mathematisch Centrum, Amsterdam, 1978. 
MR 0596583[12] VLADÁR T.: Lindenmayer systems. Growth functions and computational complexity. Diploma thesis, Faculty of Mathematics and Physics, Komensky University, Bratislava,  1981 (in Slovak).
[13] WOOD D.: 
Grammar and L-forms: An Introduction. Lecture Notes in Computer Science 91, Springer-Verlag, Berlin, 1980. 
MR 0589890 | 
Zbl 0521.68085