References
- Cheshire, M. V., Cranwell, P. A., Falshaw, C. P., Floyd, A. J., & Haworth, R. D., 1967: Humic Acid. II. Structure of humic acids. — Tetrahedron 23, 1669–1682.
- Willoughby, L. G., Baker, C. D., & Foster, S. E., 1968: Sporangium formation in the Actinoplanaceae induced by Humic Acids. — Experientia 24, 730.