→External links: Fixed a typo.
* [http://www.gasballooning.net/resources.htm A very good resource for information about and instructions for gas
balllooning]. Has links to couple of (old but good) books available in PDF format.
* [http://www.gasballooning.net/BT-2361.pdf Theory of Ballooning, War Department, 25 Apr, 1940]. The basics in 13 pages.