2台のピアノのための協奏曲
Richard and John appeared with many orchestras in Europe and North and Central America, often playing unusual repertoire. They were soloists with the Cleveland Orchestra in a 1978 revival of Victor Babin's "Concerto for Two Pianos and Orchestra"; with the Syracuse Symphony in Tibor Serly's "Double Concerto"; with the Honolulu Symphony in Quincy Porter's "Concerto Concertante for 2 Pianos and" "Orchestra"; with the American Symphony Orchestra in New York's Carnegie Hall, in Max Bruch's "Concerto for Two Pianos and Orchestra"; with the Des Moines Symphony and with the Seattle Symphony in the orchestrated version, commissioned by the Contiguglias from Tom Kochan, of Percy Grainger's "Fantasy on George Gershwin's 'Porgy and Bess". Other orchestras with which they have collaborated include the Boston Pops under Arthur Fiedler, the Toronto Symphony, the National Symphony, the Atlanta Symphony, the Pittsburgh Symphony, the Baltimore Symphony, the Colorado Symphony, the Phoenix Symphony, the Netherlands Chamber Orchestra, the Amsterdam Philharmonic, the Rotterdam Philharmonic, and the Nordelich Philharmonic Orkest of Groningen, Netherlands.