Shiva Purana
एवं बेरं च संस्थाप्यं तत्रैव परमं शुभम् । पंचाक्षरेण बेरं तु उत्सवार्थं वहिस्तथा १८ ।
Similarly the embodied image shall also be fixed there auspiciously. For the sake of festivals the embodied image shall be installed outside with the five-syllabled mantra.
english translation
evaM beraM ca saMsthApyaM tatraiva paramaM zubham । paMcAkSareNa beraM tu utsavArthaM vahistathA 18 ।
hk transliteration by Sanscript