In his appearance, manners and habits of thought, Heawood was an extravagantly unusual man. He had an immense moustache and a meagre, slightly stooping figure. He usually wore an Inverness cape of strange pattern and manifest antiquity, and carried an ancient handbag. His walk was delicate and hasty, and he was often accompanied by a dog, which was admitted to his lectures. … His transparent sincerity, piety and goodness of heart, and his eccentricity and extraordinary blend of naiveté and shrewdness secured for him not only the fascinated interest, but also the regard and respect of his colleagues.
- Percy John Heawood, MacTutor History of Mathematics Archive, St Andrews University
- Marta Macho Stadler, ¿Cuatro colores son suficientes?, Un paseo por la Geometría 2004/2005 (BI-2868/05), 97 – 114, 2005
- Marta Macho Stadler, El teorema de los cuatro colores, Las matemáticas en la vida cotidiana: Sociedad y cultura, Museo Arte e Historia de Durango, 2011