Surya Siddhanta
प्राणादिः कथितो मूर्तस् त्रुट्याद्यो +अमूर्तसम्ज्ञकः। षड्भिः प्राणैर् विनाडी स्यात् तत्षष्ट्या नाडिका स्मृता ॥
The time called Múrta, begins with Práṇa (a portion of time which contains four seconds,) and the time called Amúrta begins with Truṭi (a very small portion of time which is the 1 / 33750 th part of a second.) The time which contains six Práṇas is called a Pala, and that which contains sixty Palas is called a Ghaṭiká.
english translation
prANAdiH kathito mUrtas truTyAdyo +amUrtasamjJakaH। SaDbhiH prANair vinADI syAt tatSaSTyA nADikA smRtA ॥
hk transliteration by Sanscript