Inserting a footnote on a bibliography entry

Question

I am not trying to make footnote citation. What I am doing is citing some unpublished correspondence in my thesis. I am publishing those in an appendix. So I want to add a footnote to the bibliography pointing the reader to the appendix if they are interested in the citation.

I am using biblatex with the following command:

\usepackage[backend=biber, style=ieee]{biblatex}

The citation I want to add the footnote on looks like this in the bib file:

@misc{GRPHT_DOCS_5,
author={Keenan, Charles H.},
organization={Brookhaven National Laboratory Associated Universities Inc.},
howpublished={Private Correspondance with T. Cantwell},
title={Letter authorizing the sale of 100 tons of graphite to MIT.},
month={April},
year={1955}
},

Answer 1

This solution does not add a footnote, but places the hint in the entry directly. It was not clear to me where the footnote should be attached to.

You use the command \includefullref{<entrykey>} in the appendix when you include a copy of the full source. Everything else happens automatically: If that command was called it creates a label full:<entrykey>, if such a label is defined the corresponding bibliography entry refers to that label.

\documentclass[british]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{csquotes}

\usepackage[backend=biber, style=ieee]{biblatex}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@misc{GRPHT_DOCS_5,
  author       = {Keenan, Charles H.},
  organization = {Brookhaven National Laboratory Associated Universities Inc.},
  howpublished = {Private Correspondance with T. Cantwell},
  title        = {Letter authorizing the sale of 100 tons of graphite to MIT.},
  date         = {1955-04},
}
\end{filecontents}

\addbibresource{\jobname.bib}
\addbibresource{biblatex-examples.bib}

\renewbibmacro{finentry}{%
  \ifcsundef{r@full:\thefield{entrykey}}
    {}
    {\printtext{see section~\ref{full:\thefield{entrykey}}
       on page~\pageref{full:\thefield{entrykey}}}}%
  \finentry}

\newcommand*{\includefullref}[1]{\section{\citetitle{#1}}\label{full:#1}}

\begin{document}
\cite{sigfridsson,GRPHT_DOCS_5}
\printbibliography

\appendix
\includefullref{GRPHT_DOCS_5}
Full text here
\end{document}