Shiva Purana
भक्त्या पञ्चाक्षरेणैव पुत्रैः पुष्पैर्वनोद्भवैः ॥ समभ्यर्च्य चिरं कालं चचार परमं तपः ॥ ५४ ॥
With devotion the five syllables were offered to the sons with flowers grown in the forest. After worshiping him he performed severe austerities for a long time.
english translation
bhaktyA paJcAkSareNaiva putraiH puSpairvanodbhavaiH ॥ samabhyarcya ciraM kAlaM cacAra paramaM tapaH ॥ 54 ॥
hk transliteration by Sanscript