1. C. R. Borges, On extensions of topologies,Can. Math. J.,19 (1967), 474–487.
2. D. E. Cameron, A survey of maximal topological spaces,Top. Proc.,2 (1977), 11–59.
3. J. van Dalen and E. Wattel, A topological characterization of ordered spaces,Gen. Top. and Appl.,3 (1973), 347–354.
4. E. Deák, Theory and applications of directional structures,Coll. Math. Soc. János Bolyai 8. Topics in Topology, Keszthely (Hungary), 1972, 187–211.
5. D. J. Lutzer, On generalized ordered spaces,Dissert. Math.;89 (1971), Warszawa.