4905 20200610165701.0 CTALK-2020-0121 Hayakawa, Hisashi Hisako Koyama’s Sunspot Observations and their Digitization 2019 2019-08-22 STCE Clette, Frédéric ISSI Team Meeting 2, Recalibration of the Sunspot Number series, Bern, Switzerland frederic.clette@observatoire.be https://www.issibern.ch/teams/sunspotnoser/wp-content/uploads/2019/09/P4_13_Hayakawa_Koyama_approved.pdf Contributed CTALKCONT