Useful Links
1) Library of Free Astrology Ebooks
This link is to a website where you can download and read a huge variety of astrological texts from various eras in the past. The site is excellent and quite simple to use.
2) Mixed Elements
This link is to a website which explains the impact of mixed elements in the natal chart
http://www.thedarkpixieastrology.com/blog/mixed-elements-in-the-natal-chart