チャールズ・ファイザー
↑ Ivan Kazimour. Historie zdravotnictvi. E-knihy jedou. p. 283. ISBN 978-80-7512-758-7. https://books.google.com/books?id=tmrnDQAAQBAJ&pg=PA283 2021年2月28日閲覧。
↑ U.S. Passport Application for Charles Pfizer, May 1899; National Archives and Records Administration (NARA); Washington D.C.; NARA Series: Passport Applications, 1795-1905; Roll #: 525; Volume #: Roll 525 - 11 May 1899-19 May 1899