Philip Dormer Stanhope (4th earl of Chesterfield.), Charles Caleb Colton (1861). “Lord Chesterfield's advice to his son on men and manners. To which are added, selections from Colton's 'Lacon'.”, p.188
Joseph Lancaster (1807). “Improvements in Education, as it Respects the Industrious Classes of the Community: Containing Among Other Important Particulars, an Account of the Institution for the Education of One Thousand Poor Children, Borough Road, Southwark; and of the New System of Education on which it is Conducted”, p.148