Many of these references are available on the Internet. Where possible, the URL of all such documents is indicated, in the hope that this will make tracking down the information easier. Note that URL's tend to be capricious and change more frequently than say, the publisher of a book. In many ways, access to the Internet is necessary for research into this area, since it enables information to be transmitted quickly. There are also a number of other resources such as the gesture-l mailing list and the sci.virtual-worlds newsgroup which have been invaluable in this thesis. As you can see, some of the information in this thesis is as recent as July 1995.