| Key | Title |
| 54 | Key to the cod fishes (Gadidae) of Europe. |
| 91 | Key to the cods (Gadidae) of Canada. |
| 955 | Key to the species of true cods (Gadidae) occurring in the Western Central Atlantic. |
| 1194 | Key to species of Arctogadus. |
| 1196 | Key to species of Eleginus. |
| 1197 | Key to species of Gadus. |
| 1198 | Key to species of Microgadus. |
| 1201 | Key to species of Pollachius. |
| 1202 | Key to species of Theragra. |
| 1203 | Key to species of Trisopterus. |