Ron Alterovitz, Etienne Lessard, Jean Pouliot, I-Chow Joe Hsu, James F.
  O'Brien, and Ken Goldberg.
"<strong>Optimization of HDR brachytherapy dose distributions using linear
  programming with penalty costs</strong>".
<em>Medical Physics</em>, 33(11):4012&ndash;4019, November 2006.