Have you ever wondered if a quotation mark can have a punctuation mark outside it? Absolutely.
Chicago Manual of Style, 15th edition, University of Chicago Press, (6.8), says that periods and commas precede closing quotations marks (whether double or single).
However, it says that unlike periods and commas, colons, semicolons, question marks and exclamation points follow the closing quotation marks unless a question mark or an exclamation point belongs within the quoted matter. (6.9)
CMS uses this example:
I was asked to state my "name and serial number"; I have no serial number.
A Writer's Reference, Fourth Edition, Diana Hacker(Bedford/St. Martin's) agrees (P6-f), and gives this example:
Harold wrote, "I regret that I am unable to attend the fundraiser for AIDS research"; his letter, however, contained a substantial contribution.
There are exceptions, and alternative systems, but for the most part, the above applies to American English.
