L. H. Bailey: Geographic Distribution of Milam Apple in North America
L. H. Bailey reported in the Annals of Horticulture of North America for the Year 1892 the results of his 1891 survey of the apple varieties sold by nurserymen which was compiled from 95 fruit nursery catalogs. He found 878 varieties for sale that year. From the results he was able to estimate the geographic distribution of each apple variety. 
Annals of Horticulture in North America for the Year 1892, January 1893, page 244.