Walters, D. (2011). Demons of the Night: Quevedo's Sonnet 'A fugitivas sombras', the melancholy humour and Paracelsus. The Modern Language Review, 106(3), pp. 765-778.

Walters, David. "Demons of the Night: Quevedo's Sonnet 'A Fugitivas Sombras', the Melancholy Humour and Paracelsus." The Modern Language Review 106, no. 3 (2011): 765-778.

Walters, David. "Demons of the Night: Quevedo's Sonnet 'A Fugitivas Sombras', the Melancholy Humour and Paracelsus." The Modern Language Review 106.3 (2011): 765-778.