"Unfortunately the family data are sadly incomplete, so that only two of his children are identified...," so said Mr Reno W. Backus, author of a comprehensive Backus family book, Backus Families of Early New England. He was referring to the John Backus (6).
This is what was stated in the book regarding the family of John Backus (6) (John 5, John 4, Timothy 3, Stephen 2, William 1). John Backus (6) had six children by his first wife and eight children by his second wife (wife #2 identified as Hannah Fuller). So 13 children were NOT in the book (he had Clinton T. by wife #3). I've identified 8 children. Actually not all of his wives were identified in the book, either.
The two children named in the "Backus Families...." book were Charles and Clinton Theron Backus.
It took ten years to fit my Laura Backus Richmond into this family. However Laura was identified in the J. B. Richmond book; the Richmonds were her in-laws.