@article{01861455,
title = {Words restricted by patterns with at most 2 distinct letters.},
journal = {The Electronic Journal of Combinatorics [electronic only]},
volume = {9},
year = {2003},
zbl = {1021.05002},
language = {en},
url = {http://dml.mathdoc.fr/item/01861455}
}
Burstein, Alexander; Mansour, Toufik. Words restricted by patterns with at most 2 distinct letters.. The Electronic Journal of Combinatorics [electronic only], Tome 9 (2003) . http://gdmltest.u-ga.fr/item/01861455/