[1] C. Benzaken: Pseudo-treillis distributifs et applications III. Buletinul Institutului Politehnic din Iasi XIV (1968), 3-4, 25. MR 0256942 | Zbl 0208.29502

[2] C. Benzaken: Structures algebriques des cheminements: Pseudo-treillis, gerbiers carré nul. In: "Network and switching theory. A NATO advanced study institute" ed. by G Biorci, 1968, p. 40.

[3] R. Busacker T. Saaty: Finite graphs and networks: An Introduction with applications. McGraw-Hill, New York 1965. MR 0209176

[4] W. R. Dunn, Jr. S. P. Chan: An algorithm for testing the planarity of a graph. IEEE Transactions on Circuit Theory CT-15 (1968), 166. MR 0281544

[5] P. L. Hammer S. Rudeanu: Boolean methods in operations research and related areas. Springer-Verlag, Berlin - Heidelberg 1968. MR 0235830

[6] S. MacLane: A combinatorial condition for planar graphs. Fundamenta Mathematica 28 (1937), 22. Zbl 0015.37501

[7] J. J. Seppänen J. M. Moore: Facilities planning with graph theory. Management Science (Application) 17 (1970), B-242.