Haurongo: Douglas, Charles Edward
He whakaaturanga anō
Rārangi pukapuka
Harper, A. P. 'C. E. Douglas, explorer'. New Zealand Alpine Journal 3, No 14 (1925): 248–253
Harper, A. P. Memories of mountains and men. Christchurch, 1946
Harper, A. P. Pioneer work in the alps of New Zealand. London, 1896
Mueller, G. My dear Bannie. Ed. M. V. Mueller. Christchurch, 1958
Pascoe, J. and G. Langton, ed. Mr Explorer Douglas. Christchurch, 2016