1 January 1990 - 1 January 1991
| DOI | https://doi.org/10.48597/2XXY-BKAN |
|---|---|
| Start time | 1 January 1990 |
| Stop time | 1 January 1991 |
| DOI | https://doi.org/10.48597/VZWJ-PQXS |
|---|---|
| Start time | 1 January 1989 |
| Stop time | 1 January 1990 |
| DOI | https://doi.org/10.48597/WJY5-XUQP |
|---|---|
| Start time | 1 January 1988 |
| Stop time | 1 January 1989 |
| DOI | https://doi.org/10.48597/G2PM-EJ8Z |
|---|---|
| Start time | 1 January 1997 |
| Stop time | 1 January 1998 |
| DOI | https://doi.org/10.48597/ACP6-UGN3 |
|---|---|
| Start time | 1 January 1987 |
| Stop time | 1 January 1988 |