(原始内容存档于2013-07-01). Eicher, John H. & David J., p. 473. Eicher, John H. & David J., p. 474. Eicher, John H. & David J., pp. 473–474. Seward, William Henry, (1801–1872)
Genesis of Double Stars"(页面存档备份,存于互联网档案馆) - by George Darwin, from A.C. Seward's Darwin and Modern Science(页面存档备份,存于互联网档案馆) (1909). Archival material relating