Objects of class "person" can hold information about an
  arbitrary positive number of persons.  These can be obtained by one
  call to person() with list arguments, or by first creating
  objects representing single persons and combining these via
  c().  The format() method collapses information about persons into
  character vectors (one string for each person): the fields in
  include are selected, each collapsed to a string using the
  respective element of collapse and subsequently
  embraced using the respective element of braces, and
  finally collapsed into one string separated by white space.  If
  braces and/or collapse do not specify characters for all
  fields, the defaults shown in the usage are imputed.  The
  print() method calls the format() method and prints the
  result, the toBibtex() method creates a suitable BibTeX
  representation.
  Person objects can be subscripted by fields (using $) or by
  position (using [).
  as.person() is a generic function.  Its default method tries to
  reverse the default person formatting, and can also handle formatted
  person entries collapsed by comma or "and" (with appropriate
  white space).
  Personal names are rather tricky, e.g.,
  https://en.wikipedia.org/wiki/Personal_name.
  The current implementation (starting from R 2.12.0) of the
  "person" class uses the notions of given (including
  middle names) and family names, as specified by given
  and family respectively.  Earlier versions used a scheme based
  on first, middle and last names, as appropriate for most of Western
  culture where the given name precedes the family name, but not
  universal, as some other cultures place it after the family name, or
  use no family name.  To smooth the transition to the new scheme,
  arguments first, middle and last are still
  supported, but their use is deprecated and they must not be given in
  combination with the corresponding new style arguments.  For persons
  which are not natural persons (e.g., institutions, companies, etc.) it
  is appropriate to use given (but not family) for the
  name, e.g., person("R Core Team", role = "aut").
  The new scheme also adds the possibility of specifying roles
  based on a subset of the MARC Code List for Relators 
  (https://www.loc.gov/marc/relators/relaterm.html).
  When giving the roles of persons in the context of authoring R
  packages, the following usage is suggested.
  
    - "aut"
- (Author) Use for full authors who have made
      substantial contributions to the package and should show up in the
      package citation.
    
"com"(Compiler) Use for persons who collected code
      (potentially in other languages) but did not make further
      substantial contributions to the package.    
"ctb"(Contributor) Use for authors who have made
      smaller contributions (such as code patches etc.) but should not
      show up in the package citation.    
"cph"(Copyright holder) Use for all copyright holders.    
"cre"(Creator) Use for the package maintainer.    
"ctr"(Contractor) Use for authors who have been
      contracted to write (parts of) the package and hence do not own
      intellectual property.    
"dtc"(Data contributor) Use for persons who
      contributed data sets for the package.    
"ths"(Thesis advisor) If the package is part of a
      thesis, use for the thesis advisor.    
"trl"(Translator) If the R code is a translation from
      another language (typically S), use for the translator to R.  
  In the old scheme, person objects were used for single persons, and a
  separate "personList" class with corresponding creator
  personList() for collections of these.  The new scheme employs
  a single class for information about an arbitrary positive number of
  persons, eliminating the need for the personList mechanism.