“…[F]or behavior to be classified as stalking it must have involved 10 separate intrusions and/or communications and must have continued for a period of at least 4 weeks. The intrusions include behavior such as loitering nearby, maintaining surveillance, making approaches, and communicating by letter, e-mail, fax, graffiti, or notes attached to the victim’s car” (Roberts, 2005).

Roberts, Karl A. (2005). Women’s experience of violence during stalking by former romantic partners [Electronic Version]. Violence Against Women, 11(1), 89-114.