Kaj Grønbæk Peter Ørbæk Jannie Friis Kristensen Mette Agger Eriksen Physical hypermedia: augmenting physical material with hypermedia structures. 5-34 2003 9 The New Review of Hypermedia and Multimedia 1 http://dx.doi.org/10.1080/13614560410001725293 db/journals/nrhm/nrhm9.html#GronbaekOKE03