Hanson, Eric N.; Harvey, Tina M.; Roths, Mark A. (1991) Hanson, Eric N.; Harvey, Tina M.; Roths, Mark A. "Experiences in DBMS Implementation Using an Object-oriented Persistent Programming Language and a Database Toolkit"
Wilk, Michael R. (1991) Wilk, Michael R. "Equate: an object-oriented constraint solver" pp286-298