signed twice, titled and dated twice 'A.C. 2.69.71 Antonio Calderara Orizzonte B 1969-1971' (on the reverse). signed twice and dated twice 'A.C. 27.73 Antonio Calderara 1973' (on the reverse). signed three times and dated three times 'A. C. 3.71 Antonio Calderara 1971 Antonio Calderara 1971' (on the reverse)