Natyashastra
एककं विवधो वापि तस्याङ्गं समुदाहृतम् । अन्यस्य चतुरस्रस्य प्रवृत्तो यो विधिः स्मृतः ॥ २८१॥
Its limb is said to be either Ekaka or Vivadha, and the rule prescribed for the beginning of the final Caturasra should be followed here as well.
english translation
ekakaM vivadho vApi tasyAGgaM samudAhRtam । anyasya caturasrasya pravRtto yo vidhiH smRtaH ॥ 281॥
hk transliteration by Sanscript