@article{ITA_2008__42_4_747_0,
     author = {Tan, Bo and Wen, Zhi-Ying},
     title = {Periodicity problem of substitutions over ternary alphabets},
     journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications},
     pages = {747--762},
     publisher = {EDP-Sciences},
     volume = {42},
     number = {4},
     year = {2008},
     doi = {10.1051/ita:2007057},
     mrnumber = {2458705},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/ita:2007057/}
}