The references for the course are as follows.

Required Online References

These are considered as important as the required books for this course.

There are also many other web pages that can help you through the course listed on the links page.

Required

Optional

These references are genuinely optional. There aren't any required readings from them, or topics you need that are only covered in them. They are intended to reinforce the topics in the Guide and other references. If you'd like another explanation of any of the course material, these books will give you a good one.