| KNVB beker 1980/1981 - Appearances as Referee |  |
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| 15/11/1980 | AFC Ajax | - | SVV Schiedam | 3:0 | 1 | - | - |
| 23/01/1981 | Go Ahead Eagles | - | MVV | 3:1 | - | - | - |
| 24/02/1981 | Willem II | - | PSV Eindhoven | 0:1 | - | - | - |
| KNVB beker 1980/1981 - Appearances as Referee | |
|
|
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| 15/11/1980 | AFC Ajax | - | SVV Schiedam | 3:0 | 1 | - | - |
| 23/01/1981 | Go Ahead Eagles | - | MVV | 3:1 | - | - | - |
| 24/02/1981 | Willem II | - | PSV Eindhoven | 0:1 | - | - | - |
| Complete name: | Johannes Nicolaus Ignacius Keizer |
| Born: | 06/10/1940 |
| Place of birth: |
Volendam, 
Netherlands |
| Nationality: |
Netherlands |