@inproceedings{rohlfing2004markerless,
title = {Markerless Real-Time Target Region Tracking: Application to Frameless Sterotactic Radiosurgery},
booktitle = {International Workshop on Vision, Modelling, and Visualization (VMV)},
author = {Torsten Rohlfing and Joachim Denzler and Daniel B. Russakoff and Christoph Gräßl and Calvin R. Maurer},
year = {2004},
pages = {5--12},
}