Gajewska, Hania; Manasse, Mark S.; McCormack, Joel (October 1990). "Why X Is Not Our Ideal Window System"(PDF) (به انگلیسی). Archived from the original(PDF) on 10 September 2014. Retrieved 25 April 2014.
Gajewska, Hania; Manasse, Mark S.; McCormack, Joel (October 1990). "Why X Is Not Our Ideal Window System"(PDF) (به انگلیسی). Archived from the original(PDF) on 10 September 2014. Retrieved 25 April 2014.