Unknown Author
Luciana Maria S. de Mesquita
John R. Smith
Banco de Desenvolvimento de Minas Gerais.
Charles Thurlow
Commonwealth Institute (Great Britain)
Rita Margaret Barton
North Carolina. Division of Mineral Resources.
Adão Benvindo da Luz
Eduardo Augusto de Carvalho
I. Stabb
A. Tregellas
Peter C. Herring
Leonard Douglas Akwilapo
Západočeské továrny kaolinové a šamotové
P. B. Abeysinghe
John A. M. Vaughan
J. F. Handley
Charles Seabrook