ISBN 0-14-044383-5* Crawford, Barbara E., "An unrecognised statue of Earl Rognvald" in Crawford, Barbara E. (ed), "Northern Isles Connections: Essays from Orkney and Shetland presented to Per Sveaas Andersen.
ISBN 0-14-044383-5* Crawford, Barbara E., «An unrecognised statue of Earl Rognvald» in Crawford, Barbara E. (ed), Northern Isles Connections: Essays from Orkney and Shetland presented to Per Sveaas Andersen.