Woodhead, Nigel. Hypertext and hypermedia : theory and applications / Nigel Woodhead. - Wilmslow, England : Wokingham, England ; Reading, Mass. : Sigma Press ; Addison-Wesley Pub. Co., c1991. - x, 231 p. : ill. Cover title: Hypertext & hypermedia. ISBN: 0201544423 : $35.00 (est.) Subjects--Topical Terms: Hypertext systems.Interactive multimedia