In the context of biblatex its possible to bibstyle=reading, this will produce bibliography including abstract and annotation fields.
The annotation might come from a file named like bibannotation-TheBook2019.tex where TheBook2019 is the bib file entry key.
@book{TheBook2019,
author = {The Author},
title = {The Book Title}
}
The annotation file bibannotation-TheBook2019.tex can contain latex formated text. One might then \input{bibannotation-TheBook2019.tex} somewhere in a document. And so might be appropriate to include a citation in the bibannotation-TheBook2019.tex. Is this case it willl be self citation, I mean that file will refer to the respective entry key:
\cite{TheBook2019}
Since this information is in the file name. Can I automate it some way? So that I can just type something like:
\cite{\SelfCite}
And it will be converted to \cite{TheBook2019} grabbing the entry key from file name.

\input{bib/bibannotation-TheBook2019.tex}? – KcFnMi May 07 '19 at 04:49newcommandbe used instead ofdef? Considering https://tex.stackexchange.com/questions/655/what-is-the-difference-between-def-and-newcommand. – KcFnMi May 07 '19 at 04:55\newcommandfor\filenametokey. It (essentially) uses the technique explained in https://tex.stackexchange.com/a/662/87678. You can modify the template however you want. Just use\def\filenametokey bib/annotation-#1.tex{#1}and then\KcFnMiinput{bib/annotation-TheBook2019.tex}. (This isn't so easy to do in the MWE though, sincefilecontentscan't output to a subdirectory without--shell-escapeto create the subdirectory first if it doesn't exist.) – David Purton May 07 '19 at 05:09