1 January 1990 - 1 January 1991
| DOI | https://doi.org/10.48597/GYE8-AH97 |
|---|---|
| Start time | 1 January 1990 |
| Stop time | 1 January 1991 |
| DOI | https://doi.org/10.48597/4UV9-9KGC |
|---|---|
| Start time | 1 January 1989 |
| Stop time | 1 January 1990 |
| DOI | https://doi.org/10.48597/RWF5-GNYA |
|---|---|
| Start time | 1 January 1988 |
| Stop time | 1 January 1989 |
| DOI | https://doi.org/10.48597/UCA2-REMH |
|---|---|
| Start time | 1 January 1997 |
| Stop time | 1 January 1998 |
| DOI | https://doi.org/10.48597/JBYH-65TZ |
|---|---|
| Start time | 1 January 1987 |
| Stop time | 1 January 1988 |