THE FIVE CHORAL ARRANGEMENTS OF 'ESQUISSES GRÉGORIENNES' ARE BASED ON THE CANTUS FIRMUS MENTIONED IN EACH TITLE. THEY CAN BE INTEGRATED IN THE COURSE OF THE MASS AS FOLLOWS: 'NOS AUTEM' AT THE ENTRY, 'AVE MARIS STELLA' AT THE OFFERTORY, 'PATER NOSTER' AT 1. NOS AUTEM (ENTRÉE) - 2. AVE MARIS STELLA (OFFERTOIRE) - 3. PATER NOSTER (ELÉVATION) - 4. AVE VERUM (COMMUNION) - 5. O FILII ET FILIAE (SORTIE)