Complex sentence: To this end copies of the "Rubaiyat" (also the Talmud and Bible) are being compared to the code using computers to get a statistical base for letter frequencies although the code's being so short may require the exact edition of the book used.
Split into simpler sentences: To this end, copies of the "Rubaiyat," as well as the Talmud and Bible, are being compared to the code using computers in order to get a statistical base for letter frequencies. However, the code's short length may require the exact edition of the book used.