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. The worldwide distribution of Andisols and the need for an Andisol order in Soil Taxonomy.;Arnold,1988
3. Classification of rice growing soils.;Eswaran,1989
4. FAO/Unesco, 1964. Meeting on the Classification and Correlation of Soils from Volcanic Ash, Tokyo, Japan, 11–27 June, 1964. World Soil Resources Reports
5. FAO/Unesco, 1974. FAO-Unesco Soil Map of the World 1:5,000,000, Volume I: Legend. Unesco, Paris