“Notes on the Contents of two Viking Graves in Islay, Discovered by William Campbell, Esq., of Ballinaby; with Notices of the Burial Customs of the Norse Sea-Kings, as recorded in the Sagas and Illustrated by their Grave Mounds in Norway and in Scotland”, PSAS, vol. 14, pp. 51–89, Nov. 1880, doi: 10.9750/PSAS.014.51.89.