Yes, you are correct! In American English, the period goes before the closing quotation mark. However, in British English, it may vary depending on the style guide being followed. To verify this, you can refer to reliable grammar sources like grammar guides, style manuals, or language authority websites. The link you provided, http://grammar.ccc.commnet.edu/grammar/marks/quotation.htm, is a great resource as it provides detailed explanations and guidelines on punctuation marks within quotations. So, by consulting such sources, you can ensure that you are following the appropriate punctuation rules for your specific context. Keep up the good work with your research!