A study for the head of the prophet in an oval picture in the Collegiata San Giovanni Battista in Morbegno (R. Chiappini, Giuseppe Antonio Petrini, exhib. cat., Lugano, Villa Malpensata, 1991, no. 55). The picture was probably executed around 1734-6 for the church, along with eighteen other oval paintings of half figures commissioned from Pietro Ligari and other artists. Alternatively the picture could have been painted in 1750-52 while Petrini was working in the neighbouring church of Sant'Antonio in Morbegno.
Drawings of the same technique are in the Museo d'Arte in Lugano and private collections in Lugano and Geneva (R. Chiappini, op. cit., nos. I-II and V).