ṚV, 4, 36, 2.1 rathaṃ ye cakruḥ suvṛtaṃ sucetaso 'vihvarantam manasas pari dhyayā /

Aṣṭādhyāyī, 8, 2, 57.0 na dhyākhyāpṝmūrcchimadām //