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gouv.mc
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"Journal de Monaco : ORDONNANCES SOUVERAINES"(PDF). Journaldemonaco.gouv.mc. 16 January 1930. Retrieved 12 April 2022. Son Altesse Royale le Prince Humbert de Piémont, Prince Héritier d'Italie, est nommé Grand'Croix de l'Ordre de SaintCharles
"Den kongelige norske Sanct Olavs Orden", Norges Statskalender for Aaret 1930 (in Norwegian), Oslo: Forlagt av H. Aschehoug & Co. (w. Nygaard), 1930, pp. 995–996 – via runeberg.org