@article{ITA_1986__20_4_371_0,
     author = {Thomas, Wolfgang},
     title = {On frontiers of regular trees},
     journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications},
     pages = {371--381},
     publisher = {AFCET - Gauthier-Villars},
     address = {Paris},
     volume = {20},
     number = {4},
     year = {1986},
     mrnumber = {880841},
     zbl = {0639.68071},
     language = {en},
     url = {http://www.numdam.org/item/ITA_1986__20_4_371_0/}
}