The `cite' linkgroup includes only the \cite command
(see Citations). \cite turns each of the references in the
list into a link pointing to the respective bibliography entry
produced by the \bibliography command.
The `bib' destgroup includes the macros related to the
\bibliography command (see Citations). \bibliography
inputs a .bbl file, which contains a list of bibliography
entries. For each of the entries, a destination is defined.
Both commands use the citation label as the hyperlink label.