Cyril Hart's contributions to the Oxford Dictionary of National Biography make Ragnall, Sitriuc and Gofraid brothers; likewise Hudson, Viking Pirates, pp. 31, figure 1, makes these three brothers, sons of Guthred.
As contribucións de Cyril Hart ao Oxford Dictionary of National Biography converten a Ragnall, Sitriuc e Gofraid en irmáns; igualmente Hudson, Viking Pirates, pp. 31, figura 1, fai a estes tres irmáns fillos de Guthfrith, Rei de York.