How to remove the comma behind the institution when using it as the author and using plainnat for references

Question

I'm using natbib with a modified plainnat style to produce references while formatting authors' last names before first names. Specifically, I modified line 222 of plainnat.bst to be

{ s nameptr "{vv~}{ll,~}{ff~}{, jj}" format.name$ 't :=

There is a technical report with no author I would like to cite. I try to use the institution name as the author with double braces. The tex code is as follows.

\begin{filecontents*}{references.bib}
@techreport{lng2018,
    Author = {{The International Gas Union}},
    Institution = {The International Gas Union},
    Title = {{IGU World Gas LNG Report--2018 Edition}},
    Year = {2018}}

@techreport{kajiwara2001crude,
    Author = {Kajiwara, Shigeki},
    Institution = {The Institute of Energy Economics, Tokyo, Japan},
    Month = {July},
    Title = {Crude oil procurement by {Japanese} oil companies},
    Year = {2001}}    
\end{filecontents*}

\documentclass[11pt]{article}
\usepackage[round, colon]{natbib}
\begin{document}
Here's a reference with an institutional author \citep{lng2018}. Note that the author's last name is followed by a comma before the first name, for example, \citet{kajiwara2001crude}.
\bibliographystyle{plainnat}
\bibliography{references.bib}
\end{document}

However, there is always a comma behind the institutional author because of the format of authors. The output references are as follows.

Kajiwara, Shigeki. Crude oil procurement by Japanese oil companies. Technical report, The Institute of Energy Economics, Tokyo, Japan, July 2001.

The International Gas Union, . IGU World Gas LNG Report-2018 Edition. Technical report, The International Gas Union, 2018.

The comma behind the institutional author is annoying. I try to modify the bst file following the answer in Formatting of institution as author with natbib and numbered references, but I can't find \xfnm in my bst file, i.e., plainnat.bst. Is there any solution to this problem?

Answer 1

This is from “Tame the BeaST” (texdoc tamethebeast)

Change the line to read

{ s nameptr "{vv~}{ll}{,~ff}{, jj}" format.name$ 't :=