@article{ARM_2006__42_4_a0,
     author = {Ad\'amek, Ji\v{r}{\'\i} and H\'ebert, M. and Sousa, L.},
     title = {A logic of orthogonality},
     journal = {Archivum mathematicum},
     pages = {309--334},
     publisher = {mathdoc},
     volume = {42},
     number = {4},
     year = {2006},
     mrnumber = {2283016},
     zbl = {1156.18301},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_2006__42_4_a0/}
}