@article{Okumura:2016UL, author = "Okumura, Akira and Noda, Koji and Rulten, Cameron", title = "{ROBAST: Development of a Non-sequential Ray-tracing Simulation Library and its Applications in the Cherenkov Telescope Array }", doi = "10.22323/1.236.0951", journal = "PoS", year = 2016, volume = "ICRC2015", pages = "951" }