Yāska's Nirukta 16.2

16.2

"athāpi varṇopajana āsthad dvāro bharūjeti" | 'asu kṣepaṇe (di0 pa0 )' tasya āsthat varṇopajanena | 'vṛtūm̐ sambhaktau (krayā0 ā0 )' tasya dvāraḥ | 'bhraॅsja pāke (tu0 ubha0 )' tasya bharūjā evaṃ vyākaraṇe'pi lakṣaṇapradhāne sati arthavaśena lopāgamau vipariṇāmaśca śabdānāṃ dṛṣṭaḥ, kimuta nirukte yadarthapradhānameva | tasmāt sādhūktam,-"athānvite'rthe'prādeśike vikāre'rthanityaḥ parīkṣeta kenacid vṛttisāmānyenāvidyamāne sāmānye'pyakṣaravarṇasāmānyānnibrūyāt vibhaktīḥ, api yathārthaṃ sannamayet"-iti || evamayamādimadhyāntalopa ādimadhyāntavikāro varṇalopo dvivarṇalopa ādiviparyaya ādyantaviparyayo varṇopajanaśchandasi bhāṣāyāṃ ca draṣṭavyāḥ, dṛṣṭvā ca yathāsambhavamanuvidheyam |