| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Robert Silverberg's Many Trapdoors: Critical Essays on His Science Fiction | 978-O-313-263O8-8 (O-313-263O8-6) | 1992 | Martin Greenberg |
Carlos Elizondo · Charles E. · Charles Elsen · Charles Elson · Charles L. Elkins