Margaret Van Ess Buckwalter is the sister of Helen Van Ess, a friend of Anna Hubbard's from her time teaching at Hope College. This friendship served as a conduit for a friendly relationship between the Hubbards and the Buckwalter family, and they corresponded with and visited the Hubbards.
Margaret Buckwalter collection of Hubbard materials, 2005_104-UA, Box: 1. University of Louisville Archives and Special Collections. https://archivescatalog.library.louisville.edu/repositories/2/resources/802 Accessed July 12, 2020.