Bhaishajyaratnavali 4.58

Bhaiṣajyaratnāvalī (ed. Rājeśvaradatta Śāstrī) 4.58

madhu yatra na vidyeta tatra jīrṇo gur̤o mataḥ
purātanagur̤ābhāve raudre yāmacatuṣṭayam