1 January 1990 - 1 January 1991
| DOI | https://doi.org/10.48597/3JRF-UTJ8 |
|---|---|
| Start time | 1 January 1990 |
| Stop time | 1 January 1991 |
| DOI | https://doi.org/10.48597/PDUN-HRJH |
|---|---|
| Start time | 1 January 1989 |
| Stop time | 1 January 1990 |
| DOI | https://doi.org/10.48597/V6J8-SPUU |
|---|---|
| Start time | 1 January 1988 |
| Stop time | 1 January 1989 |
| DOI | https://doi.org/10.48597/JB9N-X8CA |
|---|---|
| Start time | 1 January 1997 |
| Stop time | 1 January 1998 |
| DOI | https://doi.org/10.48597/7RBY-VK3X |
|---|---|
| Start time | 1 January 1987 |
| Stop time | 1 January 1988 |