Pina (p. 40); Pope Eugenius IV's bull Sincere Deuotionis appointing Ferdinand to head the Order of Avis in September 1434 can be found in Monumenta Henricina, vol. V (p. 69)
Ruy de Pina, Chronica d'El Rey D. Duarte, Ch. 10; Russell, 2000: p. 151; Frei João Álvares (p. 42) suggests the prince's destination was England.
Ruy de Pina, Cronica de D. Duarte, (p. 125). Russell ((2000), pp. 182–84). A copy of the treaty of October 17, 1437 is preserved and found in Monumenta Henricina, Vol. VI, p. 211