Śaunaka Śikṣā 5

5

kādīnāṃ pañca vargāśca sparśā iti hi saṃjñitāḥ
duspṛṣṭaśceti vijñeyo ḍaḍhayossvaramadhyayoḥ

The five series beginning with 'ka' are termed 'stops' (sparśa). / And when [ḍa and ḍha] are between vowels, [the sound] should be known as duḥspṛṣṭa ('ḷa' and 'ḷha').