| Author: | Hubble, Edwin, 1889-1953 |
| Subject: | QB, Milky Way, Nebulae |
| Format: | Electronic text |
| Date issued: | 2022 |
| Language: | English |
| Publisher: | Project Gutenberg, |
| Rights: | Public domain in the USA. |
| Download link: | Extra-galactic nebulae [electronic resource] / Edwin Hubble |