| 968 / | HD | HOROLOGY |
| 524 | DD | DRIVING MECHANISMS FOR CLOCKS BY MASTER CLOCKS [G04C 13/00] {2} |
| 525 | DD | .~ Circuit arrangements; electric clock installations [G04C 13/02] {5} |
| 534 | DD | .~.~ Master clocks [G04C 13/04] {4} |
| 538 | DD | .~.~.~ Provided with supplementary means for setting or changing the time indication of the slave clocks [G04C 13/04C] {2} |
| 539 | | .~.~.~.~ For automatically correcting or compensating for disturbances [G04C 13/04C2] |