Andrzej Ehrenfeucht, Grzegorz Rozenberg, Dirk Vermeir. On ET0L Systems with Rank. J. Comput. Syst. Sci., 19(3):237-255, 1979.
@article{EhrenfeuchtRV79, title = {On ET0L Systems with Rank}, author = {Andrzej Ehrenfeucht and Grzegorz Rozenberg and Dirk Vermeir}, year = {1979}, researchr = {https://researchr.org/publication/EhrenfeuchtRV79}, cites = {0}, citedby = {0}, journal = {J. Comput. Syst. Sci.}, volume = {19}, number = {3}, pages = {237-255}, }