Natyashastra
अत ऊर्ध्वं प्रवक्ष्यामि गीतानायां सुकल्पनम् । गुरुवेदाष्टकं कृत्वा न्यसेल्लघ्वष्टकं पुनः ॥ २१४॥
Now I shall explain the arrangement of songs in brief. After completing a set of eight long syllables, one should place eight short syllables again.
english translation
ata UrdhvaM pravakSyAmi gItAnAyAM sukalpanam । guruvedASTakaM kRtvA nyasellaghvaSTakaM punaH ॥ 214॥
hk transliteration by Sanscript