- HP Lovecraft's Under the Pyramids.
- Robert E Howard's The Mirrors of Tuzun Thune.
- Clark Ashton Smith's The Garden of Adompha.
Anyway, I was wondering whether anyone had suggestions for other stories I could turn my attention to once I finish A Princess of Mars. If so, please leave a comment.
PS All four of the stories I've mentioned here can be found on en.wikisource.org.