Citti, wife of the sage Atharvā, gave birth to a son named Aśvaśirā by accepting a great vow called Dadhyañca. Now you may hear from me about the descendants of the sage Bhṛgu.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
चित्तिस्त्वथर्वणः पत्नी लेभे पुत्रं धृतव्रतम् । दध्यञ्चमश्वशिरसं भृगोर्वंशं निबोध मे
cittistvatharvaṇaḥ patnī lebhe putraṃ dhṛtavratam | dadhyañcamaśvaśirasaṃ bhṛgorvaṃśaṃ nibodha me
SB 4.1.42