[2] http://xwinman.org a list of X window managers and their feature lists.
[3] http://www.apple.com/macosx/features/expose Apple's Expose: find the window you need now, a feature in Mac OSX to help deal with screen cluttering.
[4] design principles. Last accessed on 24 Nov. 2004
[5]Window manager design principles, last accessed on 24 Nov. 2004 http://w3.pppl.gov/misc/motif/MotifStyleGuide/en_US/Window_Manager_Design_Principles.html, window manager http://biology.ncsa.uiuc.edu/library/SGI_bookshelves/SGI_Developer/books/Motif_SG/sgi_html/ch07.html
50 paper/50 model