writing style - How do I designate the footnotes that are mine inside a quote?

Note: sorry for cross-posting from Writers.SE, but I can't seem to get a definite answer.

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How do I designate the footnotes that are mine inside a quote?

I tried "our note", "note ours" and "remark is ours". Which one is the correct one and most commonly used? Or is there some other way?

For example:

He provides an argument for it:
"Before the Greeks, the ancient Egyptians
used it[1] in the construction of their great pyramids."

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[1] The Golden Section — note ours. ← this is my note, not the original author's

So you can see there is my note inside a quote.

Or if I have something without a footnote.

He provides an argument for it:
"Before the Greeks, the ancient Egyptians used it (Golden Section — note ours) in the construction of their great pyramids."

Note where I use "note ours", to clarify that "it" is a "Golden Section".

Answer

What about Author's Note?

It's generally something written at the beginning or in the end of text, but I've read that it can be used as footnote as well. I'll edit if I find more info.

EDIT: Check here.