A Comparative Study of Some of the Leading Music Systems of the 15th, 16th, 17th & 18th Centuries c11.18

सत्य लक्षणतो भेदो द्वादशानामपीष्यते ।
शुद्धेभ्यस्तत्र भेदस्तु सप्तानामेव लक्षितः ॥