Lipsey & Chrystal: Economics 11e
Chapter 16
Robert E Schenk's Cyber Economics site offers a gradual exploration of the Income-Expenditure model, introducing the various components in stages.
Ted Black's Economics Net-Textbook offers a wide variety of interactive explorations of both microeconomic and macroeconomic theory, including the simple Keynesian macro model and the consumption and savings functions. It's a bit rough in presentation terms, but it works.


