BibTex format
@article{Achtman:2015:10.1371/journal.pone.0134435,
author = {Achtman, M and Zhou, Z and Didelot, X},
doi = {10.1371/journal.pone.0134435},
journal = {PLOS One},
title = {Formal Comment to Pettengill: The Time to Most Recent Common Ancestor Does Not (Usually) Approximate the Date of Divergence},
url = {http://dx.doi.org/10.1371/journal.pone.0134435},
volume = {10},
year = {2015}
}