van Helden, A. Roemer's Speed of Light(PDF). Journal for the History of Astronomy. 1983, 14:2 (40): p. 137 [2013-07-08]. (原始内容(PDF)存档于2022-06-16). 引文格式1维护:冗余文本 (link) (页面存档备份,存于互联网档案馆)
van Helden, A. Roemer's Speed of Light(PDF). Journal for the History of Astronomy. 1983, 14:2 (40): p. 137 [2013-07-08]. (原始内容(PDF)存档于2022-06-16). 引文格式1维护:冗余文本 (link) (页面存档备份,存于互联网档案馆)