[3-1] A Light-Focusing Fiber Guide Prepared by Ion-Exchange Techniques I. Kitano, K. Koizumi, H. Matsumura, T. Uchida, M. Furukawa (1.Nippn Sheet Glass Co., Ltd., 2.Nippon Electric Co., Ltd.) https://doi.org/10.7567/SSDM.1969.3-1