Não informado. (1950). British National Bibliography. British Library, Bibliographic Services Division.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. British National Bibliography. London: British Library, Bibliographic Services Division, 1950.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. British National Bibliography. British Library, Bibliographic Services Division, 1950.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.