1 January 1990 - 1 January 1991
| DOI | https://doi.org/10.48597/Z8Q6-SDYD |
|---|---|
| Start time | 1 January 1990 |
| Stop time | 1 January 1991 |
| DOI | https://doi.org/10.48597/B7N4-486D |
|---|---|
| Start time | 1 January 1989 |
| Stop time | 1 January 1990 |
| DOI | https://doi.org/10.48597/P3YN-AQJC |
|---|---|
| Start time | 1 January 1988 |
| Stop time | 1 January 1989 |
| DOI | https://doi.org/10.48597/ZV2C-BBN9 |
|---|---|
| Start time | 1 January 1997 |
| Stop time | 1 January 1998 |
| DOI | https://doi.org/10.48597/WXQF-JYSM |
|---|---|
| Start time | 1 January 1987 |
| Stop time | 1 January 1988 |