Shiva Purana
बिल्वमूले जलैर्यस्तु मूर्द्धानमभिषिंचति । स सर्वतीर्थस्नातः स्यात्स एव भुवि पावनः २५ ।
He who pours water over his head at the root of a Bilva can be considered to have taken his bath in all sacred waters in the earth. Verily he is holy.
english translation
bilvamUle jalairyastu mUrddhAnamabhiSiMcati । sa sarvatIrthasnAtaH syAtsa eva bhuvi pAvanaH 25 ।
hk transliteration by Sanscript