Omit periods in all-cap abbreviations, unless the abbreviation is geographical or refers to a person.
Example: BA (for Bachelor of Arts), but U.S. (for United States), and P.K. (for Pernell Karl) Subban.
Some public figures are known by initials without periods (JFK – John Fitzgerald Kennedy).
Use periods in lower-case or mixed abbreviations, but not abbreviations that begin and end with a cap.
Example: i.e.; B. Comm; PhD.
Do not abbreviate professor.
Example: Professor Jones, not Prof. Jones.
For Canadian provinces and territories, use these abbreviations after the name of a community:
Alta., B.C., Man., N.B., N.L., N.W.T., N.S., Ont., P.E.I., Que., Sask.
For American states, use these abbreviations after the name of a community:
Ala., Ariz., Ark., Calif., Colo., Conn., Del., Fla., Ga., Ill., Ind., Kan., Ky., La., Md., Mass., Mich., Minn., Miss., Mo., Mont., Neb., Nev., N.H., N.J., N.M., N.Y., N.C., N.D., Okla., Ore., Pa., R.I., S.C., S.D., Tenn., Vt., Va., Wash., W.Va., Wis., Wyo.