Add additional page number, from original work, in margin

Question

In this beautiful example from frabjous the original page numbers from the source is place in the margin (below is a screenshot of page 8, which is page 9 and 10, marked by a red marker in the text, in the original)

frabjous has made a very beautiful website where the code is available, but the specif code to make the original page numbers in the margin is quite elaborate.

Does anyone here know if there is a package to do this or maybe an easier solution the the one used by frabjous?

Answer 1

After being encouraged by Werner's comment above I experimented with \marginpar{}, and after that \marginnote{}. Apparently it wasn't as complicated as I had imagined. I got this nice result with \marginnote{} (see below for code)

 \documentclass[11pt]{article}

\usepackage{lipsum}
\usepackage{marginnote}
\usepackage{color}

\begin{document}
  \lipsum[1]
   \verb!\marginpar{}! used {\color{red}$|$} \marginpar{ {\color{red}$7$}} 
    \lipsum[1] 
   \verb!\marginnote{}!  used {\color{red}$|$}  \marginnote{{\color{red}$ 8$}}
        \lipsum[1] 
\end{document}