acm_article             Association for Computing Machinery (ACM)
                        format.
acs_article             American Chemical Society (ACS) Journal format.
ctex                    A PDF format for documents based on the LaTeX
                        package 'ctex'
elsevier_article        Elsevier journal format.
jss_article             Journal of Statistical Software (JSS) format.
rjournal_article        R Journal format.
