Zanatta M., Gysel M., Bukowiecki N., Muller T., Weingartner E., Areskoug H., Fiebig M., Yttri K.E., Mihalopoulos N., Kouvarakis G., Beddows D., Harrison R.M., Cavalli F., Putaud J.P., Spindler G., Wiedensohler A., Alastuey A., Pandolfi M., Sellegri K., Swietlicki E., Jaffrezo J.L., Baltensperger U. and Laj P.: A European aerosol phenomenology-5: Climatology of black carbon optical properties at 9 regional background sites across Europe, Atmospheric Environment Vol 145 p.346 -364 Doi: 10.1016%2fj.atmosenv.2016.09.035, 2016