@article{JIS_2014__17_8_a5,
     author = {Avila,  Brandon and Khovanova,  Tanya},
     title = {Free {Fibonacci} sequences},
     journal = {Journal of integer sequences},
     year = {2014},
     volume = {17},
     number = {8},
     zbl = {1298.11013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2014__17_8_a5/}
}