(2003). Teaching and learning at a distance: Foundations of distance education. Upper Saddle River, N.J: Merrill/Prentice Hall.
Chicago-tyylinen lähdeviittausTeaching and Learning At a Distance: Foundations of Distance Education. Upper Saddle River, N.J: Merrill/Prentice Hall, 2003.
MLA-viiteTeaching and Learning At a Distance: Foundations of Distance Education. Upper Saddle River, N.J: Merrill/Prentice Hall, 2003.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.