EXTRACT: Integration of Factual and Procedural Descriptions through Object-Oriented Programming. - Ivan Popchev; I. Popov; Vasil Vasilev; V. Tadjer; G. Simov; Vesselin Bontchev (AIMSA, 1988)

Programming in Zortech C+ + - with Version 2 : J M Hughes. - G. Simov (Inf. Softw. Technol., 1992)