Shiva Purana
अथ वा मस्तकं बाहूहृदयं नाभिरेव च ११२ब्। पंचस्थानान्यमून्याहुर्धारणे भस्मविज्जनाः ११२ ।
Or these five parts are to be used for applying ashes as mentioned by those who know more about the efficacy of the ashes. They are:—forehead, two arms, chest and navel.
english translation
atha vA mastakaM bAhUhRdayaM nAbhireva ca 112b। paMcasthAnAnyamUnyAhurdhAraNe bhasmavijjanAH 112 ।
hk transliteration by Sanscript