Maurice Nivat, Ahmed Saoudi. Automata on infinite trees and Kleene closure of regular tree sets. Bulletin of the EATCS, 36:131-136, 1988.
@article{NivatS88, title = {Automata on infinite trees and Kleene closure of regular tree sets}, author = {Maurice Nivat and Ahmed Saoudi}, year = {1988}, researchr = {https://researchr.org/publication/NivatS88}, cites = {0}, citedby = {0}, journal = {Bulletin of the EATCS}, volume = {36}, pages = {131-136}, }