Mary Elizabeth Koen

• 1871 census, Guysborough County, NS, Canada
• 1871 census, Guysborough County, NS, Canada
• 1881 census of Guysborough County, Nova Scotia, Canada
• 1891 census of Guysborough County, Nova Scotia, Canada
• Census of Nova Scotia, 1860-1861
• Index to Guysborough sketches and other essays, by A.C. Jost, Guysborough, Nova Scotia, 1950
• Index to heads of families in Sydney County, Nova Scotia, census of 1817
• Index, 1838 census of Nova Scotia, Guysborough County
• The study of mathematics is an important factor in the development of the adolescent child