M. L. Siebert

A biological and chemical study of several anaerobic digesters

D. F. Toerien, P. G. Thiel, J. Kotzé, 1968 .

Determination of protein content of anaerobic digesting sludge

P. G. Thiel, P. G Thiel, W.H.J. Hattingh, 1967 .

Estimation of methane-producing bacterial numbers by the most probable number (MPN) technique

W.H.J. Hattingh, M. L. Siebert, W. Hattingh, 1967 .

Biological changes during the adaptation of an anaerobic digester to a synthetic substrate

D. F. Toerien, P. G. Thiel, J. Kotzé, 1967 .