Teague is doing research for a paper he is writing in his Business course. Teague's professor assigned an article to help students get started with their research. An excerpt of that article is presented below. Teague wants to read more about the key concept from the excerpt. Which of the sources cited in the excerpt should Teague track down in order to do that? Excerpt: Emerging management models are often indebted to older paradigms, even as they offer new ways to incorporate methods of labor control (Harris 2010). Douglas McGregor's conceptualization of Theory X and Theory Y is most influential for calling upon managers to be more reflective of their own attitudes by suggesting that they get the kinds of results they expect from their employees (McGregor 1960). If they expect deception, for example, their employees will eventually become deceptive. Richard Kopelman notes that later studies of office environments improved the validity of McGregor's theories by providing support for further operationalization of each factor (Kopelman 2008)