@article{10_37236_118,
     author = {Robert W. Chen and Burton Rosenberg},
     title = {On the first occurrence of strings},
     journal = {The electronic journal of combinatorics},
     year = {2009},
     volume = {16},
     number = {1},
     doi = {10.37236/118},
     zbl = {1160.91004},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/118/}
}