When I was a small boy, I knew Nevin Korns from when he would visit his brother (my grandfather) Allen Lester Korns in Southampton Township, Somerset County, PA. My mother told me that Nevin lived in or near Altoona, PA, worked for the railroad, and was responsible for improvements in train air brakes.
Page 84 of the 1949 book "The Genealogy of Michael Korns, Sr. of Somerset County Pennsylvania" correctly indicates that Nevin was the son of John Wilson and Mary (Geiger) Korns, and apparently incorrectly states "Nevin Lewis Korns, married Anna Longanecker. Children: Mary, Mildred and David.". I believe that "Mary, Mildred" was one daughter, instead of two. I know from my mother Estalene and my aunt Dolores that Nevin definitely had a daughter named "Mary Mildred" who was a missionary in Peru, and died there. They always call her "Mary Mildred". If I remember correctly, Mary Mildred died during child birth while in Peru, and had a son David who is about my age. I have met David several times. After his mother's death, David was adopted, and goes by his adopted surname.
According to a conversation that I had with Dolores Korns in Dec. 2007, Mary Mildred (Korns) Jones (daughter of Nevin) was the wife of Elias Jones.
Links to pages with information on Nevin Korns: