著者名,書名,版表示,出版者名,出版年,シリーズ名,番号,ISBN,ISSN,URL Great Britain. Ordnance Survey,Abergavenny and The Black Mountains : Y Fenni a'r Mynyddoedd Duon,,Ordnance Survey,1994,"1:50,000 landranger series",,031922161X,,https://cir.nii.ac.jp/crid/1130282269598115072