1) "The Orthography of South African Native Languages" in Christianity And The Natives
    of South Africa
edited by J. Dexter Taylor, Lovedale Institutional Press (no date, probably
    1930 or 1931).

2) "Foreword" in A Grammar of Central Karanga by Francisque A. Marconnes, Witwatersrand
     University Press, Johannesburg, 1931, pp. vii-viii.

3) "Click Consonants" (Chapter XIX) and "Sounds With More Than One Articulation" (Chapter XX)
     in Practical Phonetics For Students Of African Languages by D. Westermann and Ida C.
     Ward, Oxford University Press, London, 1933.

4) "Language" (Chapter XIV) in The Bantu-Speaking Tribes of South Africa: An Ethnographic
edited by I. Schapera, Routledge & Kegan Paul Ltd., London, 1937.