John Gere has kindly confirmed the attribution. An old copy of this drawing catalogued as by a follower of Vasari is at Edinburgh, K. Andrews, National Gallery of Scotland, Catalogue of Italian Drawings, Cambridge, 1968, II, pl. 847. The Edinburgh drawing has recently been attributed to Gherardi by Catherine Monbeig Goguel, Da Francesco Salviati a Cristofano Gherardi e Battista Franco, in Nuove ricerche in margine alla mostra: Da Leonardo a Rembrandt, Turin, 1990, pp. 121-3, fig. 10