| 摘要 |
<p>The invention concerns a perpetual calendar comprising centennial tables (T20-T30) representing groups of years starting with different weekdays and respectively distributed over seven columns of common years (A1-A7) and seven columns of leap years (B1-B7). Said fourteen annual calendars comprise a first series of seven annual calendars for common years (A1-A7) and a second series of annual calendars for leap years (B1-B7) starting with different weekdays and refer respectively to the groups of years (A1-A7, B1-B7) represented in the centennial tables. The inventive perpetual calendar can be used to find any one time interval desired with the appropriate centennial tables.</p> |
