'Missa ex F a 4 Vocibus Conc: et Ripieni, 2 Violinis Conc. et Ripieni, 2 Cornibus, et Organo, Violoncello con Violone, Del Sig[no]re Haydn'. Not an authenticated work of either Joseph or Michael Haydn. Includes postcard from H. C. Robbins Landon to Margaret Crum: "The Hopkinsons Mass by Haydn is not by Michael. I should catalogue it simply as Haydn, Joseph (attributed to), and leave it at that".