1. Registrar‐General's Statistical Review of England and Wales for 1922, Text, Table LXXIV, p. 138.
2. Registrar‐General's Statistical Review of England and Wales for 1932, Text, Table LXXXVIII, p. 136.
3. Statistisk Tabelvaerk (Danmark), 1926–30, 5th Ser., letter A, no. 19, p. 32 * .
4. Folkemengdens Bevegelse, 1921–32, Table k, p. 24.
5. Lewis C. J. , and Lewis J. N. , 1906. Natality and Fecundity, Table XIV, p. 29.