@article{ITA_2003__37_4_315_0,
     author = {Uustalu, Tarmo},
     title = {Generalizing substitution},
     journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications},
     pages = {315--336},
     publisher = {EDP-Sciences},
     volume = {37},
     number = {4},
     year = {2003},
     doi = {10.1051/ita:2003022},
     mrnumber = {2053030},
     zbl = {1042.18003},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/ita:2003022/}
}