Daniel Keefe, Trevor M. O'Brien, David B. Baier, Stephen M. Gatesy,
  Elizabeth L. Brainerd, and David H. Laidlaw.
  <b>Exploratory Visualization of Animal Kinematics Using
  Instantaneous Helical Axes</b>.
  <i>Computer Graphics Forum (EuroVis 2008 Special Issue)</i>,
  27(3):863-870, 2008.<br />