Retrieved 2009-06-25 .   ^ Morgan, Rik (05-08-2008). "Cragstan Periscope-Firing Range" . Handheld Museum . http://www.handheldmuseum.com/Misc/CragstanPeriscope.htm . Retrieved 2008-12-27 .   ^ "Optoelectronics Arrives" . Time 99 (14). 1972-04-03 . http://www.time.com/time/magazine/article/0,9171,903443,00.html .   ^ Morgan, Rik (05-08-2008). "Interview with Howard Cohen." . Handheld Museum . http://www.handheldmuseum.com/Mattel/Trivia.htm . Retrieved 01-10-2009 .