Shiva Purana
ततस्तपश्चरत्तं तं बालमेकाकिनं कृशम् ॥ उपमन्युं द्विजवरं शिवसंसक्तमानसम् ॥ ५५ ॥
Thereafter, the young boy, alone and emaciated, began to practice austerities. Upamanyu the best of brahmins whose mind was attached to Lord Śiva.
english translation
tatastapazcarattaM taM bAlamekAkinaM kRzam ॥ upamanyuM dvijavaraM zivasaMsaktamAnasam ॥ 55 ॥
hk transliteration by Sanscript