5. Abbreviations
5.1 Contracted forms of words are always followed by a period.
Dr., edn., St., fols., vols., nos., eds., repr., trans., vol., ed.
5.2 Acronyms do not require periods.
USA, OED, HIV, DC
5.3 For historical figures, use b. (born); d. (died); fl. (flourished); r. (ruled)
5.4 For approximate years, use c. (circa).
5.5 For references to manuscripts use MS (singular) and MSS (plural).