Burt, William Austin, 1792-1858, Ives, William (1847). 47N 47W - Survey Map of Ironwood Township and Erwin Township, Gogebic County [Michigan]. Department of Natural Resources. https://michigan.access.preservica.com/uncategorized/IO_2f5cd8e2-7962-4756-89fa-f492cdf2df04 (map)