I'm encoding a book which is a collection of letters.
The case is the following:

                               Sunday, 20 October 1837
     Dear John[1]:
     One paragraph
     Another paragraph
     etc.

At the foot of the page:
[1] Here goes the content of the note

I've encoded it as follows:

<opener>
<date>Sunday, 20 October 1837</date>
<salute>Dear John:</salute>
</opener>
<p>One paragraph</p>
<p>Another paragraph</p>
<p>etc.</p>

I've tried to insert de <note> after the word John but I'm not allowed

How can I solve this?