Merrifield, Mary Philadelphia, The Art of Fresco Painting, as Practised by the Old Italian and Spanish Masters, with a Preliminary Inquiry into the Nature of the Colours Used in Fresco Painting, with Observations and Notes, London: Printed for the Author, by Charles Gilpin, 5 Bishopsgate Street and Arthur Wallis, Brighton, 1846. https://archive.org/details/artfrescopainti00merrgoog/mode/2up