Skandapurana 5.271.3

5.271.3

māheśvarasya viprendrāḥ śrūyatāṃ gadataḥ sphuṭam ..
nimeṣasya caturbhāgastruṭiḥ syāttaddvayaṃ lavaḥ .. 3 ..

of the Great Lord, O best of brahmins; listen clearly as it is spoken: / A truṭi is the fourth part of a nimeṣa; two of them make a lava; 3.