@article{JIS_2004__7_2_a0,
     author = {Sapounakis, A. and Tsikouras, P.},
     title = {On $k$-colored {Motzkin} words},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {7},
     number = {2},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2004__7_2_a0/}
}