1. SUNDIAL WEB SITES:
   http://www.sundialsoc.org.uk/glossary/equations/equations.htm
   http://www.mts.net/~sabanski/sundial/tsp/horizontal_sundial.html
   http://www.de-zonnewijzerkring.nl/eng/easy-zonw-procedure.htm
   http://www.wsanford.com/~wsanford/exo/sundials/shadows.html
   http://perso.wanadoo.fr/blateyron/sundials/shadowspro/gb/functions.htm
   http://en.wikipedia.org/wiki/Sundial
   http://www.accuratesundials.com/site/591582/page/140934
   http://perso.wanadoo.fr/blateyron/sundials/gb/heure.html
   http://www.sundialsoc.org.uk/glossary/alpha.htm
2. MARS SUNDIAL
   http://www.planetary.org/rrgtm/marsdial/images.html
3. ANGLES
   http://mathworld.wolfram.com/topics/Angles.html
4. ASTROMONY MOVIES TO VISUALIZE THE EARTH SUN MOTION
   http://brahms.phy.vanderbilt.edu/~rknop/astromovies/index.html
5. SQUEAKLAND:
   There is a lot of useful information at the Squeakland web site. There are several tutorials and many example projects at this site. You can buy the BASIC REFERENCE listed below and a very motivating DVD on the power of Squeak at the web site.
6. GLOSSARY:
   Download and view this PDF Squeak glossary to learn the terminology and icons.
7. QUICK START:
   Download and print this Squeak Etoy Quick Start Guide to get the basics on three sheets.
8. BASIC REFERENCE:
   B. J. Allen-Conn and Kim Rose, Powerful Ideas in the Classroom: Using Squeak to Enhance Math and Science Learning, Viewpoints Research Institute, Inc. (2003). This reference is written with the elementary school teacher in mind and is an excellent primer for introducing the power of Squeak to young students. Although the authors worked with fifth graders, any K-12 teacher would benefit by refering to this reference to get started. The book can be purchased at the Squeakland web site.
9. MORE ADVANCED REFERENCES:
   1. Mark Guzdial, Squeak: Objected-Oriented Design with Multimedia Applications, Prentice Hall (2001).
   2. Mark Guzdial and Kim Rose, Squeak: Open Personal Computing and Multimedia, Prentice Hall (2002).