1 January 1990 - 1 January 1991
| DOI | https://doi.org/10.48597/44M9-6TVU |
|---|---|
| Start time | 1 January 1990 |
| Stop time | 1 January 1991 |
| DOI | https://doi.org/10.48597/DSG2-23HN |
|---|---|
| Start time | 1 January 1989 |
| Stop time | 1 January 1990 |
| DOI | https://doi.org/10.48597/NDRT-F4GT |
|---|---|
| Start time | 1 January 1988 |
| Stop time | 1 January 1989 |
| DOI | https://doi.org/10.48597/WETA-JYTQ |
|---|---|
| Start time | 1 January 1997 |
| Stop time | 1 January 1998 |
| DOI | https://doi.org/10.48597/G448-R83N |
|---|---|
| Start time | 1 January 1987 |
| Stop time | 1 January 1988 |