Infrastructure for extended formulas with multiple parts on the
             right-hand side and/or multiple responses on the left-hand side.
c(person(given = "Achim", family = "Zeileis", role = c("aut", "cre"), email = "Achim.Zeileis@R-project.org"),
             person(given = "Yves", family = "Croissant", role = "aut", email = "Yves.Croissant@univ-reunion.fr"))
Achim Zeileis [aut, cre],
  Yves Croissant [aut]