signé 'Rotella' (en bas à droite); signé 'Rotella' (sur le châssis); signé, daté et inscrit 'SPIRALE Rotella / 61' (au revers). signed 'Rotella' (lower right); signed 'Rotella' (on the stretcher); signed, dated and inscribed 'SPIRALE Rotella / 61' (on the reverse)