Natyashastra
वस्वादौ वसुमध्ये च वस्वन्ते या निवृत्तयः । प्रयोक्तव्यः प्रयोगज्ञैर्विचार्याङ्गबलाबलम् ॥ १२२॥
After considering the relative strength (lit. strength and weakness) of the different limbs of a Vastu, the expert musician should observe the repetition at its beginning, middle or conclusion.
english translation
vasvAdau vasumadhye ca vasvante yA nivRttayaH । prayoktavyaH prayogajJairvicAryAGgabalAbalam ॥ 122॥
hk transliteration by Sanscript