Grammar Girl's Punctuation 911 Quotes

“In the United States, periods and commas go inside the quotation mark. In Britain, they go outside the quotation mark. Squiggly said, “No.” (United States) Squiggly said, “No”. (Britain)   “No,” said Squiggly. (United States) “No”, said Squiggly. (Britain)”
― Mignon Fogarty, Grammar Girl's Punctuation 911: Your Guide to Writing it Right