Bluebook Rule (21st): 2.1
Casenames
You should use ordinary plain text for case names in full citations, except for procedural phrases like ex rel., which are italicized.
Books
You should use large and small capitals for book authors and titles.
Periodicals
The article title is italicized. Periodical names are in large and small capitals. Authors' names are in ordinary type.
Introductory signals
All introductory signals should be in italics when they appear within citation sentences or clauses.
Punctuation
Commas, semicolons, and other punctuation marks should only be in italics if they are part of the italicized material, not when they are simply an element of the sentence or citation in which they appear.
Bluebook Rule (21st): 2.2
The main body text of law review articles should be in ordinary typeface, except for case names and the titles of publications, speeches, or articles, all of which are italicized. Other words may be italicized for emphasis or similar stylistic purposes.
Footnote text
Case names appearing in footnotes should be italicized when they are grammatically part of the sentence. When cases are parts of citation clauses in footnotes, they should not be italicized. Any other authority in a footnote should use the typeface convention for a full or short citation.
Punctuation
Punctuation like commas and semicolons should only be italicized when they are part of the italicized material, and not when they are part of the citation or sentence in which they appear.