@inproceedings{
    belacg,
    author = "Bollob{\'a}s, B. and Das, G. and Gunopulos, D. and Mannila, Heikki",
    booktitle = "13th Annual ACM Symposium on Computational Geometry",
    year = "1997",
    pages = "454-456",
    title = "Time-series similarity problems and well-separated geometric sets"
}