| Europa League 1964/1965 - Appearances as Referee |  |
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| 28/10/1964 | Wiener Sport-Club | - | Ferencvárosi TC | 1:0 | - | - | - |
| 27/01/1965 | Athletic Bilbao | - | Dunfermline Athletic | 1:0 | - | - | - |
| Europa League 1964/1965 - Appearances as Referee | |
|
|
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| 28/10/1964 | Wiener Sport-Club | - | Ferencvárosi TC | 1:0 | - | - | - |
| 27/01/1965 | Athletic Bilbao | - | Dunfermline Athletic | 1:0 | - | - | - |
| Complete name: | Karl Keller |
| Born: | 01/04/1923 |
| Place of birth: |
Switzerland |
| Residence: | Basel |
| Nationality: |
Switzerland |