1. Andisol TU Database, 1992 Database on Andisols from Japan, Alaska, and northwestern U.S.A. Prepared by Soil Science Laboratory, Tohoku University (see Appendix 2)
2. Differential weathering of volcanic ash and pumice, resulting in formation of hydrated halloysite;Aomine;Am. Miner.,1962
3. Kaolinite defect structures; possible relation to allophanes;Brindley;Proc. Int. Clay Conf. 1969,1969
4. Iron oxide mineralogy of placic horizons;Campbell;J. Soil Sci.,1984
5. Natural ferrihydrites in surface deposits from Finland and their association with silica;Carlson;Geochim. Cosmochim. Acta.,1981