Brockman, Frederick Slade; Pether, H. J; Western Australia. Royal Commission on the Agricultural Industries of Western Australia. Progress report of the Royal Commission on the Agricultural Industries of Western Australia on the wheat-growing portion of the south-west division of the State, together with minutes of evidence, indices, and appendices (1917), Map shewing the wheat growing areas of the State of Western Australia with Brockman's Line of rainfall as its Northerly & Easterly boundaries, Surveyor General's Dept.?, retrieved 11 February 2014{{citation}}: CS1 maint: multiple names: authors list (link)