Extended principle of orthogonal database designEessaar, ErkiProceedings of the 5th WSEAS International Conference on Artificial Intelligence, Knowledge Engineering and Data Bases : Madrid, Spain, February 15-17, 20062006 / p. 360-365 https://www.researchgate.net/publication/255599595_Extended_Principle_of_Orthogonal_Database_Design

Some algorithms for data table (re)ordering using monotone systemsVõhandu, Leo; Kuusik, Rein, inform.; Torim, Ants; Aab, Eik; Lind, GreteProceedings of the 5th WSEAS International Conference on Artificial Intelligence, Knowledge Engineering and Data Bases : Madrid, Spain, February 15-17, 20062006 / p. 417-422