The first known documented use of 'workplace bullying' is in 1992 in a book by Andrea Adams called Bullying at Work: How to Confront and Overcome It. Research has also investigated the impact of the larger organizational context on bullying as well as the group-level processes that impact on the incidence and maintenance of bullying behaviour. Bullying can be covert or overt. It may be missed by superiors; it may be known by many throughout the organization. Negative effects are not limited to the targeted individuals, and may lead to a decline in employee morale and a change in organizational culture. It can also take place as overbearing supervision, constant criticism, and blocking promotions.