Crawford, R.J.M. (2005) Cape Gannet. In: Hockey, P.A.R., Dean, W.R.J., Ryan, P.G. and Maree, S. (Eds) Roberts Birds of Southern Africa, 7th Edition.John Voelcker Bird Book Fund, Cape Town.
Crawford, R.J.M. (2006) Pers. comm.
Crawford, R.J.M., Dundee, B.L., Dyer, B.M., Klages, N.T., Meÿer, M.A. and Upfold, L. (2007) Trends in numbers of Cape gannets (Morus capensis), 1956/57-2005/06, with a consideration of the influence of food and other factors. ICES Journal of Marine Science, 64: 0 - . Available at: http://icesjms.oxfordjournals.org/cgi/content/abstract/fsl011v1