%0 Journal Article %A Halava, Vesa %A Harju, Tero %A Kärki, Tomi %T The theorem of Fine and Wilf for relational periods %J RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications %D 2009 %P 209-220 %V 43 %N 2 %I EDP-Sciences %U https://doi.org/10.1051/ita:2008025 %R 10.1051/ita:2008025 %G en %F ITA_2009__43_2_209_0