Botoeva E., Kostov Y., Petrov E. A reliable linear constraint solver for the UniCalc system // Computer Science. — 2006. — # 24 — P. 45-55
Zagorulko Y., Kostov Y., Popov I. Subdefinite data types and constraints in knowledge representation language // Computer Science. — 2001. — # 16 — P. 153-170
