ṛṣibhiḥ bahudhā gītam chandobhiḥ vividhaiḥ pṛthak brahma sūtra padaiḥ ca eva hetu madbhiḥ viniścitaiḥ
That knowledge of the field of activities and of the knower of activities is described by various sages in various Vedic writings. It is especially presented in Vedānta-sūtra with all reasoning as to cause and effect.