More about kofun (links)
To learn more about kofun:
Osaka Prefecture Chikatsu Asuka Museum
To learn more about the Mozu-Furuichi Tomb Clusters (of which Nonaka Kofun is a part):
■About the Mozu-Furuichi Tomb Clusters, currently on the Tentative List for World Heritage Sites
Osaka Prefecture Board of Education (in Japanese only)
http://www.pref.osaka.jp/bunkazaihogo/bunkazai/sekaiisan.html
Urban Attraction Division, Urban Attraction Creation Bureau, Department of Civic and Cultural Affairs, Osaka Prefectural Government (in Japanese only)
http://www.pref.osaka.jp/toshimiryoku/sekaiisan/index.html
■About Furuichi Tomb Cluster
Fujiidera City Official Site (Historic Heritage > Library: Furuichi Tomb Cluster > Column: Message from Ancient Times) (in Japanese only)
http://www.city.fujiidera.lg.jp/9.html
Habikino City Official Site
http://www.city.habikino.lg.jp/
■Mozu Tomb Cluster
Sakai City Official Site (The Digital Burial Mound Encyclopedia)
http://www.city.sakai.lg.jp/kanko/rekishi/dkofun/index.html
■Excavations by the Osaka University Department of Archaeology
http://www.let.osaka-u.ac.jp/kouko/
http://www.let.osaka-u.ac.jp/kouko/hpnagaoyama2011/index2011.htm