| Passive ownership stake (update) | SC 13G/A | 1998-02-11 | - |
| Quarterly report | 10-Q | 1997-10-21 | 1997-09-30 |
| Quarterly report | 10-Q | 1997-07-22 | 1997-06-30 |
| Employee plan annual report | 11-K | 1997-06-30 | 1996-12-31 |
| Employee plan annual report | 11-K | 1997-06-30 | 1996-12-31 |
| Employee plan annual report | 11-K | 1997-06-30 | 1996-12-31 |
| Employee plan annual report | 11-K | 1997-06-30 | 1996-12-31 |
| Employee stock plan | S-8 | 1997-06-25 | - |
| Quarterly report | 10-Q | 1997-04-14 | 1997-03-31 |
| Annual report | 10-K | 1997-03-25 | 1996-12-31 |
| Proxy statement | DEF 14A | 1997-03-04 | 1997-04-14 |
| Passive ownership stake | SC 13G | 1997-02-13 | - |
| Prospectus supplement | 424B2 | 1996-12-05 | - |
| Quarterly report (amended) | 10-Q/A | 1996-11-07 | 1996-09-30 |
| Quarterly report | 10-Q | 1996-10-23 | 1996-09-30 |
| Quarterly report | 10-Q | 1996-07-25 | 1996-06-30 |
| Employee plan annual report | 11-K | 1996-06-25 | 1995-12-31 |
| Employee plan annual report | 11-K | 1996-06-25 | 1995-12-31 |
| Employee plan annual report | 11-K | 1996-06-25 | 1995-12-31 |
| Employee plan annual report | 11-K | 1996-06-25 | 1995-12-31 |
| 8-A12B | - | 1996-06-11 | - |
| Major company event | 8-K | 1996-06-07 | 1996-06-04 |
| Passive ownership stake (update) | SC 13G/A | 1996-05-22 | - |
| Quarterly report | 10-Q | 1996-05-13 | 1996-03-31 |
| Securities registration | S-3 | 1996-03-26 | - |
| Annual report | 10-K | 1996-03-20 | 1995-12-31 |
| Proxy statement | DEF 14A | 1996-02-27 | 1996-04-15 |
| Passive ownership stake (update) | SC 13G/A | 1996-02-14 | - |
| Passive ownership stake | SC 13G | 1996-02-12 | - |
| Employee stock plan | S-8 | 1995-12-20 | - |
| Employee stock plan | S-8 | 1995-12-20 | - |
| Employee stock plan | S-8 | 1995-12-20 | - |
| Employee stock plan | S-8 | 1995-12-20 | - |
| Employee plan annual report | 11-K | 1995-12-18 | 1994-12-31 |
| Employee plan annual report | 11-K | 1995-12-18 | 1994-12-31 |
| Employee plan annual report | 11-K | 1995-12-18 | 1994-12-31 |
| Employee plan annual report | 11-K | 1995-12-18 | 1994-12-31 |
| Quarterly report | 10-Q | 1995-11-13 | 1995-09-30 |
| Quarterly report | 10-Q | 1995-08-14 | 1995-06-30 |
| Quarterly report | 10-Q | 1995-05-11 | 1995-03-31 |
| Annual report | 10-K | 1995-03-27 | 1994-12-31 |
| Proxy statement | DEF 14A | 1995-02-28 | 1995-04-10 |
| Passive ownership stake | SC 13G | 1995-02-16 | - |
| Activist ownership stake (update) | SC 13D/A | 1994-11-15 | - |
| Passive ownership stake (update) | SC 13G/A | 1994-02-14 | - |
