Chang JY, Zhang X, Knopf A, Li H, Mori S, Dong L, Lu HM, Liu W, Badiyan SN, Both S, Meijers A, Lin L, Flampouri S, Li Z, Umegaki K, Simone CB, Zhu XR. Consensus Guidelines for Implementing Pencil-Beam Scanning Proton Therapy for Thoracic Malignancies on Behalf of the PTCOG Thoracic and Lymphoma Subcommittee. Int J Radiat Oncol Biol Phys. 2017 09 01; 99(1):41-50.