| Europa League 1969/1970 - Appearances as Referee |  |
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 |
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| 10/09/1969 | RSC Anderlecht | - | Valur Reykjavík | 6:0 | - | - | - |
| 16/09/1969 | FC Carl Zeiss Jena | - | Altay Izmir | 1:0 | - | - | - |
| 18/03/1970 | Arsenal FC | - | SC Bacau | 7:1 | - | - | - |
| Europa League 1969/1970 - Appearances as Referee | |
|
|
||||
| 10/09/1969 | RSC Anderlecht | - | Valur Reykjavík | 6:0 | - | - | - |
| 16/09/1969 | FC Carl Zeiss Jena | - | Altay Izmir | 1:0 | - | - | - |
| 18/03/1970 | Arsenal FC | - | SC Bacau | 7:1 | - | - | - |
| Complete name: | Wilhelmus Jacobus Maria Schalks |
| Born: | 21/03/1923 † 25/10/2017 |
| Place of birth: |
Leiden, 
Netherlands |
| Residence: | Leiden |
| Nationality: |
Netherlands |