The last part, VI. Conclusion, from the nonfiction book Mars (1895).
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| April 1967 |
|
The Coming of the Space Age | Meredith Press | Nonfiction | 202 |
| 1970 |
|
The Coming of the Space Age | Panther | Nonfiction | 221 |