@article{ijar17,
    author = {Christoph Beierle and Tobias Falke and Steven Kutsch and Gabriele Kern-Isberner},
    title = {System Z^FO: Default Reasoning with System Z-like Ranking Functions for Unary First-Order Conditional Knowledge Bases},
    journal = {International Journal of Approximate Reasoning},
    volume = {90},
    number = {Supplement C},
    year = {2017},
    pages = {120--143},
    url = {http://dx.doi.org/10.1016/j.ijar.2017.07.005}
}