Ministry of Health, Labour and Welfare (Japan). Introductory Chapter, Annual Report on Health, Labour and Welfare 2002-2003. Saitama: Gyosei Co. ltd, Saitama, 2004: 2-5.
Suzuki N. Construction Library 12: Discussion of residence.-Present Japanese dwelling history based on experience description-.: Kenchiku siryou kenkyusha. Tokyo.2002 (in Japanease).
Pet Food Manufacturers Association: The data page; The Pet-Related Data, Whole Country Findings of Dog and Cat Keeping Rates, No.12 Whole Country Findings, The Place of Kreeping Dogs, The Place of Keeping Cats. Pet Food Manufacturers Association (in Japanese).: URL: http://www.jppfma.org/ (Accessed.May.2006)
Pet Food Manufacturers Association: The data page; The Pet-Related Data, Whole Country Findings of Dog and Cat Keeping Rates, Trifle breeding head count and a breeding rate graph (First-No.10). Pet Food Manufacturers Association (in Japanese). URL: http://www.jppfma.org/shiryo/shiryo-set.html (Accessed.May.2006).