Use periods with abbreviations that end in a lowercase letter. An exception may be made for the few academic degrees that end in a lowercase letter (e.g., DLitt, DMin).
p. (page), vol., e.g., i.e., etc., a.k.a., a.m., p.m., Ms., Dr., et al. (et is not an abbreviation; al. is)
Use periods for initials standing for given names, but do not use periods for an entire name replaced by initials: JFK.
E. B. White, JFK
Use no periods with abbreviations that include two or more capital letters, even if the abbreviation also includes lowercase letters: .
VP, CEO, MA, MD, PhD, UK, US, BC, PEng
When referring to provinces and states, prefer postal abbreviations, which do not include periods
US, BC, AB
No space is left between the letters of initialisms and acronyms, whether lowercase or in capitals. Space is usually left between abbreviated words, unless an abbreviated word is used in combination with a single-letter abbreviation.