i. Research by Ronald Blacknell [208]; [Source Record]
ii. 1939 Register. RG 101. The National Archives of the UK, London; Page Wrexham, Wilfred Blacknell household.; [Source Record]; Certainty Primary Evidence
iii. Personal knowledge of Judith Blacknell.; [Source Record]; Certainty Primary Evidence
iv. Blacknell, Daniel. Wrexham, Denbighshire. Interview questionnaire by Paul Blacknell. Transcript. Privately held by Paul Blacknell .; [Source Record]