Links

A hypertext system is made of nodes (concepts) and links (relationships).

Links connect related concepts or nodes. They can be bidirectional thus facilitating backward traversals. Links can also be typed (such as specification link, elaboration link, membership link, opposition link and others) specifying the nature of relationship.^{[Rao & Turoff, 1990]} Links can be either referential (for cross-referencing purposes) or hierarchical (showing parent-child relationships). Activation of link markers display nodes.