H.J. Zwart, P. Hartman and A. C. Tobi (1984) “To Professor Dr. Emile den Tex - on the occasion of his retirement from the chair of Petrology, Mineralogy and Crystallography, which he held at the State Universities of Leiden (since 1959) and Utrecht (1978-1983)”, Netherlands Journal of Geosciences, pp. 129-130. Available at: https://njgjournal.nl/index.php/njg/article/view/13295 (Accessed: 1April2026).