W. F. Brewer and G. V. Nakamura, The Nature and Functions of Schemas, C# and VB.NET-Gang of Four (GOF), pp.119-160, 1984.

E. Gamma, R. Helm, R. Johnson, J. Vlissides, C. Novac-ududec et al., Design Patterns: Elements of Reusable Object-Oriented Software (GOF)Agent Intelligent Platform for Student Tutoring, Proc. SEFI-IGIP 2007, pp.65-69, 1995.