| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Contributions to the 15th International Cosmic Ray Conference of IUPAP, Plovdiv, Bulgaria, August 1977 | 978-963-371-327-3 (963-371-327-7) | 1977 |
C C · C.R. · C. Ray · Cosmic Ray · I.C. · I.C.C. · I.R. · I RAY · International Conference · International R · R. C. · RAY C