| Passive ownership stake (update) | SC 13G/A | 1998-01-30 | - |
| Quarterly report | 10-Q | 1997-11-13 | 1997-09-30 |
| Quarterly report | 10-Q | 1997-08-13 | 1997-06-30 |
| Employee plan annual report | 11-K | 1997-07-15 | 1996-12-31 |
| Major company event (amended) | 8-K/A | 1997-07-02 | 1997-04-18 |
| NT 11-K | - | 1997-07-01 | 1996-12-31 |
| Passive ownership stake | SC 13G | 1997-06-02 | - |
| Passive ownership stake | SC 13G | 1997-06-02 | - |
| Quarterly report | 10-Q | 1997-05-13 | 1997-03-31 |
| Major company event | 8-K | 1997-05-05 | 1997-04-18 |
| Proxy statement | DEF 14A | 1997-04-21 | 1997-05-21 |
| Annual report | 10-K | 1997-03-27 | 1996-12-31 |
| Passive ownership stake (update) | SC 13G/A | 1997-02-13 | - |
| Passive ownership stake (update) | SC 13G/A | 1997-02-05 | - |
| Passive ownership stake (update) | SC 13G/A | 1997-01-24 | - |
| Passive ownership stake | SC 13G | 1997-01-10 | - |
| Quarterly report | 10-Q | 1996-11-14 | 1996-09-30 |
| Quarterly report | 10-Q | 1996-08-09 | 1996-06-30 |
| Employee stock plan | S-8 | 1996-06-12 | - |
| Quarterly report | 10-Q | 1996-05-14 | 1996-03-31 |
| Annual report | 10-K | 1996-03-26 | 1995-12-31 |
| Proxy statement | DEF 14A | 1996-03-04 | 1996-03-04 |
| Passive ownership stake (update) | SC 13G/A | 1996-02-15 | - |
| Passive ownership stake (update) | SC 13G/A | 1996-02-14 | - |
| Passive ownership stake | SC 13G | 1996-02-14 | - |
| Passive ownership stake (update) | SC 13G/A | 1996-02-09 | - |
| Quarterly report | 10-Q | 1995-11-13 | 1995-09-30 |
| Quarterly report | 10-Q | 1995-08-14 | 1995-06-30 |
| Quarterly report | 10-Q | 1995-05-12 | 1995-03-31 |
| 10-K405 | - | 1995-03-22 | 1994-12-31 |
| Proxy statement | DEF 14A | 1995-03-01 | 1995-04-05 |
| Passive ownership stake (update) | SC 13G/A | 1995-02-14 | - |
| Passive ownership stake (update) | SC 13G/A | 1995-02-13 | - |
| Passive ownership stake (update) | SC 13G/A | 1995-02-10 | - |
| PRE 14A | - | 1995-02-06 | 1995-03-05 |
| Employee stock plan | S-8 | 1994-12-13 | - |
| 8-A12B | - | 1994-12-05 | - |
| Quarterly report | 10-Q | 1994-11-07 | 1994-09-30 |
| Quarterly report | 10-Q | 1994-08-10 | 1994-06-30 |
| Quarterly report | 10-Q | 1994-05-06 | 1994-03-31 |
| Annual report | 10-K | 1994-03-23 | 1993-12-31 |
| Proxy statement | DEF 14A | 1994-03-02 | 1994-04-13 |
| Passive ownership stake (update) | SC 13G/A | 1994-02-14 | - |
| Passive ownership stake (update) | SC 13G/A | 1994-02-14 | - |
| Passive ownership stake (update) | SC 13G/A | 1994-02-14 | - |
| Passive ownership stake | SC 13G | 1994-02-14 | - |
