Textbooks are not always cheap and the students’ budget is not always large. Keeping this in mind, viagra many authors chose to offer their textbook on-line for free download while still charging the printed and bound copy. This has seemingly become more popular in the fields of mathematics than electrical engineering, allergist but it looks like the trend is catching on in both fields. Here is a thorough list of books available for download from the Georgia Institute of Technology School of Mathematics ( onlinebooks.html ). Two books that I find useful that they left off are Numerical Recipes by Press and the Handbook of Mathematical Functions by Abramowitz and Stegun.