The Self-4.0 User Interface - Manifesting a System-wide Vision of Concreteness, Uniformity, and Flexibility - http://research.sun.com/self/papers/self4.0UserInterface.html
Sun Labs: Self papers - Where Morphic began, as a prototype-based implementation. Here are html Morphic User Interface papers, as part of the Self, prototype-based, object oriented programming language. - http://research.sun.com/self/papers/papers.html
Where is Squeak Headed? - Morphic's home now, as a class-based implementation, in a new, open source, graphics model for Smalltalk, based on the Morphic interface to Self. Much simpler and yet more general than the model used in many other object oriented languages: MVC. - http://st-www.cs.uiuc.edu/squeak/headed.html
Janak on Morphic UI - A few useful tips for once you get going, and a bit of opinion/critique. - http://www.cc.gatech.edu/fac/mark.guzdial/squeak/morphicui.html
Getting Started with Morphic - One screenshot(!) and brief description of how to begin. - http://www.cc.gatech.edu/fac/mark.guzdial/squeak/startingmorphic.html
A John Maloney page - Tiny, third-party page on one of Morphic's two main inventors who is still working on Morphic. - http://minnow.cc.gatech.edu/squeak.385