In 1993, communication scholars Denis McQuail and Sven Windahl referred to Lasswell's model as "perhaps the most famous single phrase in communication research." McQuail and Windahl also considered the model as a formula that would be transformed into a model once boxes were drawn around each element and arrows connected the elements. In 1995, Stanley Baran and Dennis Davis recognized it a verbal model of the communication process. In 2008, Greenberg and Salwen acknowledged that Lasswell's model of communication has been widely adopted, but expressed: "Although Lasswell's model draws attention to several key elements in the mass communication process, it does no more than describe general areas of study. It does not link elements together with any specificity, and there is no notion of an active process.