“…(Baldwin, Clark, 2000) and also (Cai, Sullivan, 2006), (Sethi, et al 2009). DSM and other matrices, such as Kusiak and Huang's (Kusiak, Huang, 1997) (Baldwin, Clark, 2000) that "it is difficult to base modularity on functions… hence their definition of modularity is based on relationships among structures, not functions". See (Ulrich, 1995) for a different view.…”