| nsta.org | National Science Teachers Association |
| hrw.com | Holt, Rinehart and Winston |
| thegateway.org | The Gateway To Educational Materials - Lesson Plans, Curriculum Units And Other |
| psigate.ac.uk | PSIgate - Physical Sciences Information Gateway |
| merlot.org | MERLOT (Multimedia Educational Resource for Learning and Online Teaching) |
| hrw.com | Hrw |
| 4teachers.de | 4teachers.de |
| howstuffworks.com | Howstuffworks - Learn How Everything Works! |
| coolmath.com | Coolmath.com - An Amusement Park Of Mathematics... And More! |
| yahooligans.com | Yahooligans |
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