by their descendants.
From Netherby discussion forum July 2013:
I am a descendant of John and Eliza Adams. Their daughter Fanny Adams was my grandmothers(Dorothy Payne) grandmother, and their daughter Emma was my grandfathers(Noel Boardman) grandmother. Noel and Dorothy are my fathers parents. They were actually third cousins.
I have recently just taken an interest in genealogy and have found that my grandmother did a lot of work regarding my ancestors.