@techreport{Parberry2014TR2,
  author = {Parberry, Ian},
  title = {A Memory-Efficient Method for Fast Computation of Short 15-Puzzle Solutions},
  institution = {Laboratory for Recreational Computing, Dept. of Computer Science \& Engineering,
                 Univ.\ of North Texas},
  number = {LARC--2014--02},
  year = {2014},
  month={April},
 }