| KNVB beker 1967/1968 - Appearances as Referee |  |
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 |
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| 31/12/1967 | USV Elinkwijk | - | FC Hilversum | 5:1 | - | - | - |
| 25/02/1968 | De Volewijckers | - | Blauw Wit | 0:2 | - | - | - |
| 24/03/1968 | ZFC Zaandam | - | DWS Amsterdam | 1:1 | - | - | - |
| KNVB beker 1967/1968 - Appearances as Referee | |
|
|
||||
| 31/12/1967 | USV Elinkwijk | - | FC Hilversum | 5:1 | - | - | - |
| 25/02/1968 | De Volewijckers | - | Blauw Wit | 0:2 | - | - | - |
| 24/03/1968 | ZFC Zaandam | - | DWS Amsterdam | 1:1 | - | - | - |
| Complete name: | Johannes Nicolaus Ignacius Keizer |
| Born: | 06/10/1940 † 18/11/2024 |
| Place of birth: |
Volendam, 
Netherlands |
| Nationality: |
Netherlands |