| Tetraedron minimum | | 1990-06-26 | 1990-06-26 | Tretjønnet (Agder, Norway) |  |
| Tetraedron minimum | | 1989-09-19 | 1989-09-19 | Grindheimsvatnet (Agder, Norway) | |
| Tetraedron minimum | | 1990-09-28 | 1990-09-28 | Vikerauntjønna (Trøndelag, Norway) | |
| Tetraedron minimum | | 1990-09-28 | 1990-09-28 | Vikerauntjønna (Trøndelag, Norway) | |
| Tetraedron minimum | | 1989-09-19 | 1989-09-19 | Vikerauntjønna (Trøndelag, Norway) | |
| Tetraedron minimum | | 1991-09-07 | 1991-09-07 | Dælivannet (Akershus, Norway) | |
| Tetraedron minimum | | 1989-09-07 | 1989-09-07 | Dælivannet (Akershus, Norway) | |
| Tetraedron minimum | | 1989-09-22 | 1989-09-22 | Haukvatnet (Trøndelag, Norway) | |