@inproceedings{ mitchell91extension,
    author = "John Mitchell and Sigurd Meldal and Neel Madhav",
    title = "An extension of {Standard {ML}} modules with subtyping and inheritance",
    booktitle = "Conference record of the {E}ighteenth {A}nnual {ACM} {S}ymposium on {P}rinciples of {P}rogramming {L}anguages",
    month = "January",
    address = "Orlando, FL",
    year = "1991",
    url = "citeseer.nj.nec.com/mitchell91extension.html" }