Jan Douma, Klaus Helbig, Floris Schokking and Johan Tempels (1990) “Shear-wave splitting in shallow clays observed in a multi-offset and walk-around VSP”, Netherlands Journal of Geosciences, pp. 417-428. Available at: https://njgjournal.nl/index.php/njg/article/view/12881 (Accessed: 5April2026).