- [S122] Debrett's Peerage and Baronetage, (Debrett's Peerage Limited and Macmillan Publishers Ltd, 2000, retrieved from http://www.xreferplus.com;).
- [S112] Civil Registration Death Indexes 1837-, General Register Office, death registration of Winnafreda Dawson-Damer (Countess of Portarlington), - FE 1886, Bracknell 19 0018, June quarter 1975 (Reliability: 2).
- [S205] FreeBMD, (www.freebmd.org.uk;), marriages of Lionel A H S Dawson-Damer (Earl of Portarlington) and Winnafreda Yuill share reference Chelsea 1a 691, March quarter 1907 (Reliability: 2).
- [S9] London, England, Marriages and Banns, 1754-1921, Ancestry.com, (online database linked to digital images of records from the London Metropolitan Archives and Guildhall Library, 2009;).
1907. Marriage solemnized at Trinity Church in the Parish of Upper Chelsea in the County of London. No. 195. Second February 1907. Lionel Arthur Henry Seymour Dawson-Damer, 23, Bachelor, Earl of Portarlington, Emo Park, Portarlington, Queens County, father: George Henry Lionel Dawson-Damer (Deceased, Earl of Portarlington; & Winnifreda Yuill, 21, Spinster, 7 Cadogan Gardens, father: George Skelton Yuill, Merchant. Married in the Parish Church according to the Rites and Ceremonies of the Established Church after Banns by me, Edgar Sheppard DD (? of the Chapels Royal). This Marriage was solemnized between us, Portarlington, Winnifreda Yuill, in the Presence of us, G.S. Yuill, M. Scott, E.A. Portarlington, Henry B. Portman