Natyashastra
द्विकत्रिकचतुष्कास्तु ज्ञेया वंशगताः स्वराः । कम्प्यमानार्थमुक्ताश्च व्यक्तमुक्तास्तथैव च ॥ २ ॥
The notes produced by the bamboo flute are known to have two, three, and four Śrutis. They are either shaken (kampita), half-open (ardhamukta), or fully open (vyaktamukta).
english translation
dvikatrikacatuSkAstu jJeyA vaMzagatAH svarAH । kampyamAnArthamuktAzca vyaktamuktAstathaiva ca ॥ 2 ॥
hk transliteration by Sanscript