@article{ITA_1990__24_4_327_0,
     author = {Culik II, Karel and Karhum\"aki, Juhani},
     title = {Loops in automata and {HDTOL} relations},
     journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications},
     pages = {327--337},
     publisher = {EDP-Sciences},
     volume = {24},
     number = {4},
     year = {1990},
     mrnumber = {1079718},
     zbl = {0701.68079},
     language = {en},
     url = {http://www.numdam.org/item/ITA_1990__24_4_327_0/}
}