Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) T. R. Astin,Septarian crack formation in carbonate concretions from shales and mudstones,Clay Minerals,0009-8558,Mineralogical Society,1986-10,21,4,617-631,https://cir.nii.ac.jp/crid/1361137045012061696,https://doi.org/10.1180/claymin.1986.021.4.12