Professor Giulio Bora has kindly confirmed the attribution to Luini, on the basis of a photograph, in a communication dated 26 February 2004.
The head seen in profile in the lower left of the present drawing is very similar to another on a sheet of studies at Christ Church, Oxford, which was identified as of Luini by Philip Pouncey and A.E. Popham (J. Byam Shaw, Drawings by Old Masters at Christ Church, Oxford, Oxford, 1976, no. 1140, pl. 690).