Skandapurana 16.22.21

16.22.21

trairātrikāḥ sāṃtapanā nirāhārāstathā pare ..
kecitpuṣpa phalāhārāḥ śīrṇaparṇāśinastathā .. 21 ..

observing three-night fasts, sāṃtapana penances, and others taking no food; / some eating fruits and flowers, and eating fallen dry leaves;