Manusmriti
अह्ना चैकेन रात्र्या च त्रिरात्रैरेव च त्रिभिः । शवस्पृशो विशुध्यन्ति त्र्यहादुदकदायिनः ॥ ६४ ॥
Those who have touched a corpse are purified after one day and night (added to) three periods of three days; those who give libations of water, after three days.
english translation
ahnA caikena rAtryA ca trirAtraireva ca tribhiH । zavaspRzo vizudhyanti tryahAdudakadAyinaH ॥ 64 ॥
hk transliteration by Sanscript