George Forbes, “History of Astronomy” (New York: G. P. Putnam’s Sons, 1909)., 1909., Acc.13827/1061. Further papers of the Forbes and Stuart Forbes families of Fettercairn and Pitsligo, with papers of the Trefusis family relating to Fettercairn and Pitsligo., Acc.13827/1-1103. National Library of Scotland Archives and Manuscripts Division. https://nlssb.as.atlas-sys.com/repositories/2/archival_objects/134727 Accessed September 23, 2024.