Grai, J. A.; Schweitzer, J. S.; Draxler, J. K.; Gatto, H.; Lauterjung, J. (1993): Elemental logging in the KTB pilot hole - I. NaI-based spectrometry. Nuclear geophysics : a journal of nuclear techniques in the earth and environmental sciences, minerals exploration, mining and process control, 7, 173-187.