Nasica, "Mémoires," p. 192.
Both letters are accepted as authentic by Jung, "Bonaparte et son Temps," vol. i., pp. 84, 92; but Masson, "Napoléon Inconnu," vol. i., p. 55, tracking them to their source, discredits them, as also from internal evidence.
Chaptal, "Mes Souvenirs sur Napoléon," p. 177.
Joseph Buonaparte, "Mems.," vol. i., p. 29. So too Miot de Melito, "Mems.," vol. i., ch. x.