BibTex format
@article{Milne:2015:10.1103/PhysRevA.92.012311,
author = {Milne, A and Jennings, D and Rudolph, T},
doi = {10.1103/PhysRevA.92.012311},
journal = {PHYSICAL REVIEW A},
title = {Geometric representation of two-qubit entanglement witnesses},
url = {http://dx.doi.org/10.1103/PhysRevA.92.012311},
volume = {92},
year = {2015}
}