The First Six Books of Euclid was based on Clavius 's Latin version of Euclid 's Elements which Ricci had studied under Clavius 's guidance while in Rome.
Ang Unang Six Books ng Euclid ay batay sa Clavius' s Latin bersyon ng Euclid 's Sangkap na Ricci had-aral sa ilalim ng Clavius' s patnubay habang sa Roma.