Traversi, R., Becagli, S., Poluianov, S., Severi, M., Solanki, S. K., Usoskin, I. G., et al. (2016). The Laschamp geomagnetic excursion featured in nitrate record from EPICA-Dome C ice core. Sci. Rep., 6: 20235. doi:10.1038/srep20235.