@article{articlef87e8f8f,
title   = {Has the earth´s sixth mass extinction already arrived?},
author = {Barnosky, Anthony D and Matzke, Nicholas and Tomiya, Susumu and Wogan, Guinevere O. U and Swartz, Brian and Quental, Tiago and Marshall, Charles and McGuire, Jenny L and Lindsey, Emily L and Maguire, Kaitlin C and Mersey, Ben and Ferrer, Elizabeth A},
year = {2011},
doi = {10.1038/nature09678},
journal   = {Nature}
}