M. K. Greig, C. Greig, A. N. Shepherd, and I. A. G. Shepherd, “A beaker cist at Chapelden, Tore of Troup, Aberdour, Banff and Buchan District, with a note on the orientation of beaker burials in north-east Scotland”, PSAS, vol. 119, pp. 73–81, Nov. 1990.