Href Is the URL of the file for which you are defining a relationship. Type in a path, or click the folder icon to browse to and select a file. ID Specifies a unique identifier for the link.
Title Describes the relationship.
Rel Specifies the relationship between the current document and the document in the Href field. Possible values include Alternate, Stylesheet, Start, Next, Prev, Contents, Index, Glossary, Copyright, Chapter, Section, Subsection, Appendix, Help, and Bookmark. To specify more than one relationship, separate values with a space. Possible values are the same as for Rel.