GRO Reference
UK General Register Office
Quarter, Year, Registration area etc of Births (with Mother's Maiden Name) and Deaths.
Some GRO records (Birth/Death record images) are also sourced here as "GRO Reference".
The cited information was sourced from Website / URL <
https://www.gro.gov.uk/gro/content/certificates/indexes_search.asp> The author/originator was HM Passport Office. This citation is considered to be direct and primary evidence used, or by dominance of the evidence.