Shiva Purana
शिवावतारोऽश्वत्थामा महाबलपराक्रमः ॥ त्रैलोक्यमुखदोऽद्यापि वर्तते जाह्नवीतटे ॥ ४२ ॥
The incarnation of Śiva Aśvatthāman of great strength and exploit is even now alive on the banks of the river Gaṅgā bestowing happiness on the three worlds.
english translation
zivAvatAro'zvatthAmA mahAbalaparAkramaH ॥ trailokyamukhado'dyApi vartate jAhnavItaTe ॥ 42 ॥
hk transliteration by Sanscript