BibTeX
@ARTICLE{
         Sawyer1984Fpd,
       AUTHOR = "Sawyer, Jr., J. W.",
       TITLE = "First partial differentiation by computer with an application to categorical data
         analysis",
       JOURNAL = "The American Statistician",
       VOLUME = "38",
       YEAR = "1984",
       PAGES = "300--308",
       REFERRED = "[Iri1991HoA]."
}