“…Numerous important results, including but not limited to Amato, Celentano, and Garofalo (1993), Desoer (1969), Garcia, Peres, and Tarbouriech (2010), Guo and Rugh (1995), Ilchmann, Owens, and Prätzel-Wolters (1987), Jetto and Orsini (2009), Kamen, Khargonekar, and Tannembaum (1989), Krause and Kumar (1986), Mullhaupt, Buccieri, and Bonvin (2007), Solo (1994) and Tan and Duan (2009), have been obtained through the efforts…”