Āpastambaśulbasūtra with the commentaries of Kapardin, Karavinda and Sundararāja 21.9

दीर्घचतुरश्राणां पक्षपुच्छानां समासविधिरूक्तः । "यदन्यत्सप्तभ्यऽ इत्यादिना विधासप्तमकरणीमित्यादिना (च) वा । वेणुत्रिकरण्या वा विहरेदित्यर्थः ॥ एकविंशो ऽग्निर्भवतीत्य् अश्वमेधे विज्ञायते

dīrghacaturaśrāṇāṃ pakṣapucchānāṃ samāsavidhirūktaḥ / "yadanyatsaptabhya' ityādinā vidhāsaptamakaraṇīmityādinā (ca) vā / veṇutrikaraṇyā vā viharedityarthaḥ // ekaviṃśo 'gnirbhavatīty aśvamedhe vijñāyate

Devanagari rendered by HREEM from the edition's roman (IAST) text; the IAST is the edition's own.

Sanskrit only: no published translation is held for this verse.