Instrumental Duet,Piano Flute,Instrumental Duet,Piano,Violin - Digital Download SKU: A0.923430 By Dean Martin. By Luis Demetrio Traconis Molina and Pablo Beltran Ruiz. Arranged by Jenny Walker. Pop. Score and parts. 4 pages. J Walker #6431831. Published by J Walker (A0.923430). Pablo Beltrán Ruiz was a Mexican composer and band leader most famous for composing the Spanish language song ¿Quién será?. This was later made famous by crooner, Dean Martin, who sang the English version as 'Sway', with lyrics by Norman Gimbel.  This version was written for an instrumental trio called Motif, based in Grantham, UK.  The rhythmic drive is provided by the piano and the melodic lines are taken by the other two instruments (flute and violin).