@phdthesis{Doh:1991:262271,
    author = {Patrick Doherty},
    title = {{NML3: a non-monotonic formalism with explicit defaults}},
    year = {1991},
    series = {Link\"oping Studies in Science and Technology. Dissertations},
    volume = {258},
    publisher = {Link\"opings tekniska h\"ogskola},
    school = {Link"opings universitet},
    institution = {Link"opings universitet, Department of Computer and Information Science},
    isbn = {91-7870-816-8},
    issn = {0345-7524},
}

@phdthesis{Doh:1990:262875,
    author = {Patrick Doherty},
    title = {{A three-valued approach to non-monotonic reasoning}},
    year = {1990},
    type = {Licentiate Thesis},
    series = {Link\"oping Studies in Science and Technology. Thesis},
    volume = {230},
    publisher = {Link\"oping University},
    school = {Link"opings universitet},
    institution = {Link"opings universitet, Department of Computer and Information Science},
    isbn = {9178706726},
    issn = {0280-7971},
}