William Penn (1726). “A Collection of the Works of William Penn: To which is Prefixed a Journal of His Life, with Many Original Letters and Papers Not Before Published”, p.852
William Penn (1812). “The Sandy Foundation Shaken, Or Those So Generally Believed and Applauded Doctrines of One God, Subsisting in Three Distinct and Separate Persons [etc.] Refuted, from the Authority of Scriptures Testimonies and Right Reason”, p.6
Thomas Clarkson, William Penn (1827). “Memoirs of the private and public life of William Penn: who settled the state of Pennsylvania, and founded the city of Philadelphia”
William Penn (1807). “Fruits of solitude in reflections and maxims relating to the conduct of human life: Also, his advice to his children relating to their civil and religious conduct, to which are added extracts from the writings of William Law & Judge Hale; with a "Description of the happy man & true gentleman."”, p.92
Thomas Clarkson, William Penn (1827). “Memoirs of the private and public life of William Penn: who settled the state of Pennsylvania, and founded the city of Philadelphia”, p.124