7David A. Wiley. Connecting learning objects to instructional design theory: A definition, a metaphor, and a taxonomy[DB/OL].http://www.reusability.org/read/chapters/wiley.doc.
10A.P. Sheth. Changing Focus on Interoperability in Information Systems: From System, Syntax, Structure to Semantics[DB/OL].http://lsdis.cs.uga.edu/fibrary/download/S98-changing.pdf.