@article {RGB2011a,
   author = {Rand, Alexander and Gillette, Andrew and Bajaj, Chandrajit},
   title = {Quadratic Serendipity Finite Elements on Polygons Using Generalized Barycentric Coordinates},
   journal = {Mathematics of Computation},
   volume = {83},
   number = {290},
   year = {2014},
  pages = {2691--2716}
}