Without too much trouble I found my uncle in the database in a list from 1935. William Sartorius is listed with his wife in Amisk, Alberta, Canada. The second image in this post includes details about exactly what district in which they were living at the time. The third image contains the index entry from Ancestry.com.
I'm not yet certain precisely how to cite this, but these images provide enough detail that anyone who wants to go back and get the original can do that.
The database is actually titled "Canada, Voters Lists, 1935-1980."