@inproceedings{Kopper:2016DR, author = "Kopper, Claudio and Giang, William and Neilson, Naoko Kurahashi", title = "{Observation of Astrophysical Neutrinos in Four Years of IceCube Data}", doi = "10.22323/1.236.1081", booktitle = "Proceedings of The 34th International Cosmic Ray Conference {\textemdash} PoS(ICRC2015)", year = 2016, volume = "236", pages = "1081" }