In the phar-w file, I have put bibl tags within both prons and defs - such that every seg has a sister bibl - e.g:

<entry>
<form>
<pron><seg type="phonemic">sʕʷáʔʕʷaʔ</seg><bibl>Y1.68; MW; EP</bibl></pron>
<pron><seg type="narrow">swáʔwaʔ</seg><bibl>G48; J3.1; A4</bibl>
</pron>
<pron><seg type="narrow">swˀáʔwˀaʔ</seg><bibl>CS18</bibl></pron>

<hyph><m sameAs="nom">s</m>‐√<m sameAs="ʕWaʔ">ʕʷáʔ</m>+<m sameAs="CHAR">CVC</m></hyph>

<note>onomatopoeic<bibl>Y</bibl></note>
</form>
<sense>
<def><seg>cougar</seg>
<bibl>Y1.68; MW; EP</bibl>
<bibl>G48; J3.1; A4</bibl>
<bibl>CS18</bibl>
</def>
</sense>

I am going to do this even in cases where the entry has only one form and one def (rather than just putting the bibl on the whole entry).
This also serves to distinguish among phonemic representations:
-If it was transcribed by MDK, it has a bibl.
-If it was derived by ECH from a narrow transcription, it has no bibl.

I checked with Martin, and he agreed that this way makes sense, so I am going to change the s-rtr file to use this system too.

Martin questioned the stacking of bibl tags in the example above, where multiple sources all give the same definition. These could all actually be in a single bibl tag, but Martin can collapse them into one programmatically later. I will keep my eyes out for any cases where this would NOT work.