SSAATTBB choir unaccompanied - Digital Download SKU: OX.9780193539273 Composed by Robert Pearsall. Edited by Blaise Compton. Sheet music. Oxford Choral Classics Octavos. Octavo. 7 pages. Oxford University Press Digital #9780193539273. Published by Oxford University Press Digital (OX.9780193539273). ISBN 9780193539273.For SSAATTBB choir unaccompanied. Adapted from Pearsall's own eight-part madrigal 'Lay a garland' (also available from OUP), 'Tu es Petrus' is replete with fine polyphonic writing and rich, expressive sonorities, reflecting his enduring interest in early music and the Renaissance style.