@article{DMTCS_2008_10_1_a2,
     author = {Halava, Vesa and Harju, Tero and K\"arki, Tomi},
     title = {Interaction properties of relational periods},
     journal = {Discrete mathematics & theoretical computer science},
     publisher = {mathdoc},
     volume = {10},
     number = {1},
     year = {2007-2008},
     doi = {10.46298/dmtcs.419},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.46298/dmtcs.419/}
}