| Author: | United States. War Department. Division of Military Aeronautics |
| Subject: | UG, Balloons, Aerial observation (Military science), Military reconnaissance, Aerial reconnaissance |
| Format: | Electronic text |
| Date issued: | 2023 |
| Language: | English |
| Publisher: | Project Gutenberg, |
| Rights: | Public domain in the USA. |
| Download link: | Balloon observation, and instructions on the subject of work in the basket [electronic resource] / United States. War Department. Division of Military Aeronautics |