Added a reference paper for iMatrix-511MG.

Dr. Jun Takahashi in CiRA published a new paper. <Japanese> <English> Pre-clinical study of induced pluripotent stem cell-derived dopaminergic progenitor cells for Parkinson’s disease Doi D, Magotani H, Kikuchi T, Ikeda M, Hiramatsu S, Yoshida K, Amano N, Nomura M, Umekage M, Morizane A, Takahashi J. Nat Commun. 2020 Jul 6;11(1):3369. Doi: 10.1038/s41467-020-17165-w. 32632153