Shiva Purana
एकं शिखायां रुद्रा क्षं चत्वारिंशत्तु मस्तके । द्वात्रिंशत्कण्ठदेशे तु वक्षस्यष्टोत्तरं शतम् ३७ ।
One Rudraksha bead should be worn on the topknot (śikhā), Forty on the head, Thirty-two on the neck, and one hundred and eight on the chest.
english translation
ekaM zikhAyAM rudrA kSaM catvAriMzattu mastake । dvAtriMzatkaNThadeze tu vakSasyaSTottaraM zatam 37 ।
hk transliteration by Sanscript