Reference: Tucker et al. 1977

Tucker, Archie N., Margaret A. Bryan & James Woodburn. 1977. The East African Click Languages: A Phonetic Comparison. In G. Moehlig and Franz Rottland and Bernd Heine (eds.), Zur Sprachgeschichte und Ethnohistorie in Afrika, 300–323. Berlin: Dietrich Diener Verlag.

@incollection{tucker1977east,
  address   = {Berlin},
  author    = {Tucker, Archie N. and Margaret A. Bryan and James Woodburn},
  booktitle = {Zur Sprachgeschichte und Ethnohistorie in Afrika},
  editor    = {G. Moehlig and Franz Rottland and Bernd Heine},
  pages     = {300–323},
  publisher = {Dietrich Diener Verlag},
  title     = {The East African Click Languages: A Phonetic Comparison.},
  year      = {1977}
}