Bibliographies should be marked up using list elements. Unordered lists are appropriate for traditional print bibliographies, as the alphabetization of entries does not infer sequential order (i.e. the bibliography can be reverse sorted without losing meaning).
To facilitate navigating a bibliography, use nested lists to enclose alphabetically- and numerically-related entries.
The use of lists is recommended as it simplifies navigation by users of assistive technologies. Not only does it speed up the movement through entries, but the position within the list can be announced, allowing the reader to quickly return to the same spot again later, if needed.