BibTex format
@article{Halliwell:2013:10.1103/PhysRevA.87.022114,
author = {Halliwell, JJ and Yearsley, JM},
doi = {10.1103/PhysRevA.87.022114},
journal = {PHYSICAL REVIEW A},
title = {Negative probabilities, Fine's theorem, and linear positivity},
url = {http://dx.doi.org/10.1103/PhysRevA.87.022114},
volume = {87},
year = {2013}
}