Upper bound on the packing density of regular tetrahedra and octahedra

Authors: 

Simon Gravel, Veit Elser and Yoav Kallus,

Discrete Comput. Geom. 46 799-818 (2010)

http://arxiv.org/abs/1008.2830

http://link.springer.com/article/10.1007%2Fs00454-010-9304-x