1 January 1990 - 1 January 1991
| DOI | https://doi.org/10.48597/HHV2-KC7G |
|---|---|
| Start time | 1 January 1990 |
| Stop time | 1 January 1991 |
| DOI | https://doi.org/10.48597/E5RQ-78GN |
|---|---|
| Start time | 1 January 1989 |
| Stop time | 1 January 1990 |
| DOI | https://doi.org/10.48597/KZH2-6UFX |
|---|---|
| Start time | 1 January 1988 |
| Stop time | 1 January 1989 |
| DOI | https://doi.org/10.48597/2UUJ-JCY8 |
|---|---|
| Start time | 1 January 1997 |
| Stop time | 1 January 1998 |
| DOI | https://doi.org/10.48597/87HY-KWUY |
|---|---|
| Start time | 1 January 1987 |
| Stop time | 1 January 1988 |