Some bibliographic reference lists are unnumbered, some are bulleted lists, some have a counting number before each reference, and some have special symbols or author-descriptive labels (such as [Piez 2009]) constructed according to “Harvard rules” or other semantic numbering system. The first decision a publisher or archive needs to make is whether to capture such numbers using <label> or whether all such designators are generated for display or print. A repository archive may choose to preserve all numbers; a publisher may choose to generate them.

Assuming numbers will be preserved, the next decision concerns punctuation and spacing. It is possible to preserve all punctuation and spacing “3.” or “[Lapeyre-Usdin 2009]” or to preserve just the significant portion of the label (the numeral or the name-year) and not preserve the spacing or punctuation: “3” or “Lapeyre-Usdin 2009”.

Usually the label applies to the reference (<ref>). Citations (<element-citation> or <mixed-citation>) are typically only numbered when multiple citations occur within a single reference. In such cases, the reference is typically numbered in series with the other, single references, and the citations are numbered using a different numbering scheme. For example, a reference numbered <label>4.</label> could have citations inside it labeled “a.”, “b.”, “c.”; or “[Gaylord 2005]”, “[Beck 2006]”, “[Usdin 2009]”.