@incollection{kd09,
    author = {Kyprianidis, Jan Eric and Döllner, Jürgen},
    booktitle = {ShaderX7 - Advanced Rendering Techniques},
    publisher = {Charles River Media},
    title = {Real-Time Image Abstraction by Directed Filtering},
    year = {2009},
    pages = {285--302},
}