Shiva Purana
अघोरबीजमंत्रेण करयोर्धारयेत्सुधीः । पंचदशाक्षग्रथितां वामदेवेन चोदरे ४१ ।
The wise devotee shall wear the Rudrākṣa round the forearms with Aghora Bīja mantra. A string of fifteen beads shall be worn on the stomach with Vāmadeva mantra.
english translation
aghorabIjamaMtreNa karayordhArayetsudhIH । paMcadazAkSagrathitAM vAmadevena codare 41 ।
hk transliteration by Sanscript