London Museum of Practical Geology — 1921, printed 1922. Édition, PHI-E-000000000184. Philemone, version publique 1, publiée le 2026-10-10. https://philemone.com/editions/PHI-E-000000000184/london-museum-of-practical-geology-1921-printed-1922 (consulté le 2026-10-30).