Williams, E. T., & Palmer, H. M. (1971). The Dictionary of National Biography: Twenthieth Century: Ed. by E[dgar] T[revor] Williams and Helen M[aud] Palmer. Oxford Univ. Press.

Williams, Edgar Trevor, and Helen Maud Palmer. The Dictionary of National Biography: Twenthieth Century: Ed. by E[dgar] T[revor] Williams and Helen M[aud] Palmer. Oxford: Oxford Univ. Press, 1971.

Williams, Edgar Trevor, and Helen Maud Palmer. The Dictionary of National Biography: Twenthieth Century: Ed. by E[dgar] T[revor] Williams and Helen M[aud] Palmer. Oxford Univ. Press, 1971.