Abiteboul S., Hull R., Vianu V. Foundations of Databases. 1995;Addison-Wesley, Reading, MA.
M.H. Böhlen, R.T. Snodgrass, M.D. Soo, Coalescing in temporal databases, in: Proceedings of the International Conference on Very Large Data Bases, Morgan Kaufmann Publishers, Los Altos, CA, 1996, pp. 180-191.
Clifford J., Dyreson C., Isakowitz T., Jensen C.S., Snodgrass R.T. On the semantics of "now" in databases. ACM Transactions on Database Systems. 22(2):1997;171-214.
Dey D., Barron T.M., Storey V.C. A complete temporal relational algebra. VLDB Journal: Very Large Data Bases. 5(3):1996;167-180.
O.H. Ibarra, J. Su, On the containment and equivalence of database queries with linear constraints (extended abstract), in: Proceedings of the ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, ACM Press, New York, 1997, pp. 32-43.
Kanellakis P.C., Kuper G.M., Revesz P.Z. Constraint query languages. Journal of Computer and System Sciences. 51(1):1995;26-52.
Klug A. On conjunctive queries containing inequalities. Journal of the ACM. 35(1):1988;146-160.
Lorentzos N.A., Mitsopoulos Y.G. SQL extensions for interval data. IEEE Transactions on Knowledge and Data Engineering. 9(3):1997;480-499.
McKenzie L.E. Jr., Snodgrass R.T. Evaluation of relational algebras incorporating the time dimension in databases. ACM Computing Surveys. 23(4):1991;501-543.
Snodgrass R.T. Overview of temporal databases. Zaniolo C., Ceri S., Faloutsos C., Snodgrass R., Subrahmanian V.S., Zicari R. Advanced Database Systems. 1997;99-126 Morgan Kaufmann, San Francisco. (Chapter 5).
Snodgrass R.T. TSQL2. Zaniolo C., Ceri S., Faloutsos C., Snodgrass R., Subrahmanian V.S., Zicari R. Advanced Database Systems. 1997;127-147 Morgan Kaufmann, San Francisco. (Chapter 6).
Toman D. Point-based temporal extensions of SQL and their efficient implementation. Etzion O., Jajodia S., Sripada S. Temporal Databases: Research and Practice. vol. 1399:1998;211-237 Springer-Verlag, Berlin.
Ullman J.D. Principles of Database and Knowledge-Base Systems, vol. II. 1989;Computer Science Press, Rockville, MD.
van der Meyden R. The complexity of querying indefinite data about linearly ordered domains. Journal of Computer and System Sciences. 54(1):1997;113-135.
J. Wijsen, A. Bès, Temporal tableaux queries, in: Proceedings of the Eighth International Symposium on Temporal Representation and Reasoning, TIME 2001, IEEE Computer Society Press, 2001, pp. 136-143.