@article{ITA_2009__43_2_209_0, author = {Halava, Vesa and Harju, Tero and K\"arki, Tomi}, title = {The theorem of {Fine} and {Wilf} for relational periods}, journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications}, pages = {209--220}, publisher = {EDP-Sciences}, volume = {43}, number = {2}, year = {2009}, doi = {10.1051/ita:2008025}, zbl = {1166.68035}, mrnumber = {2512255}, language = {en}, url = {http://www.numdam.org/articles/10.1051/ita:2008025/} }