- [S33] Burke's Peerage and Gentry Website, (http://www.burkes-landed-gentry.com;), 107th edition, De Montmorency lineage (Reliability: 2).
- [S205] FreeBMD, (www.freebmd.org.uk;), birth registration of Ann M de Montmorency, Thomas, Eton 3a 1849, September quarter 1911 (Reliability: 2).
- [S112] Civil Registration Death Indexes 1837-, General Register Office, death registration of Ann Marion Swanton, born 2 Jul 1911, Nov 1998, Canterbury D2T 5601D 57 (Reliability: 3).
- [S113] Civil Registration Marriage Indexes, General Register Office, (1837-;), marriage of George H. Carbutt and Ann M. De Montmorency, London C. 1c 20, March quarter 1935 (Reliability: 3).
- [S205] FreeBMD, (www.freebmd.org.uk;), marriages of Reymond Hervey de Montmorency & Gwynedd Maud Thomas share reference St. Geo. H. Sq. 1a 908, June quarter 1905 (Reliability: 2).