| 424B3 | - | 1998-12-14 | - |
| 424B3 | - | 1998-12-11 | - |
| Prospectus supplement | 424B5 | 1998-12-08 | - |
| Prospectus supplement | 424B2 | 1998-11-12 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-11-10 | - |
| Quarterly report | 10-Q | 1998-11-06 | 1998-09-30 |
| 424B3 | - | 1998-10-26 | - |
| 424B3 | - | 1998-10-26 | - |
| 424B3 | - | 1998-10-26 | - |
| 424B3 | - | 1998-10-20 | - |
| 424B3 | - | 1998-09-18 | - |
| Securities registration | S-3 | 1998-09-08 | - |
| Quarterly report | 10-Q | 1998-08-12 | 1998-06-30 |
| Passive ownership stake (update) | SC 13G/A | 1998-08-07 | - |
| 424B3 | - | 1998-07-28 | - |
| 424B3 | - | 1998-07-28 | - |
| 424B3 | - | 1998-07-24 | - |
| 424B3 | - | 1998-07-24 | - |
| 424B3 | - | 1998-07-23 | - |
| 424B3 | - | 1998-07-17 | - |
| Employee plan annual report | 11-K | 1998-06-29 | 1997-12-31 |
| Employee plan annual report | 11-K | 1998-06-29 | 1997-12-31 |
| Employee plan annual report | 11-K | 1998-06-29 | 1997-12-31 |
| Employee plan annual report | 11-K | 1998-06-29 | 1997-12-31 |
| Employee stock plan | S-8 | 1998-06-24 | - |
| Employee stock plan | S-8 | 1998-06-24 | - |
| Employee stock plan | S-8 | 1998-06-24 | - |
| Prospectus supplement | 424B2 | 1998-05-15 | - |
| Quarterly report | 10-Q | 1998-05-14 | 1998-03-31 |
| 10-K405 | - | 1998-03-30 | 1997-12-31 |
| Proxy statement | DEF 14A | 1998-03-26 | 1998-05-01 |
| Passive ownership stake | SC 13G | 1998-02-13 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-11 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-04 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-01-27 | - |
| Passive ownership stake | SC 13G | 1997-12-09 | - |
| Quarterly report | 10-Q | 1997-11-13 | 1997-09-30 |
| Major company event | 8-K | 1997-10-15 | 1997-09-30 |
| Quarterly report | 10-Q | 1997-08-13 | 1997-06-30 |
| Employee plan annual report | 11-K | 1997-06-26 | 1996-12-31 |
| Employee plan annual report | 11-K | 1997-06-26 | 1996-12-31 |
| Employee plan annual report | 11-K | 1997-06-26 | 1996-12-31 |
| Major company event | 8-K | 1997-05-27 | 1997-05-27 |
| Quarterly report | 10-Q | 1997-05-15 | 1997-03-31 |
| Passive ownership stake (update) | SC 13G/A | 1997-05-09 | - |
| Employee stock plan | S-8 | 1997-05-07 | - |
| Major company event | 8-K | 1997-03-28 | 1996-10-17 |
| Annual report | 10-K | 1997-03-26 | 1996-12-31 |
| Proxy statement | DEF 14A | 1997-03-24 | 1997-05-02 |
| Passive ownership stake | SC 13G | 1997-01-31 | - |
