@inproceedings{ngd07,
    author = {Nienhaus, Marc and Gooch, Bruce and Döllner, Jürgen},
    booktitle = {ACM SIGGRAPH sketches},
    title = {Light threads: illustrating movement dynamics in city models},
    year = {2007},
    pages = {1},
    publisher = {ACM Press},
    doi = {10.1145/1278780.1278782},
}