Mahabharata 12.169.2
भीष्म उवाच · bhīṣma uvāca
अत्राप्युदाहरन्तीममितिहासं पुरातनम्पितुः पुत्रेण संवादं तन्निबोध युधिष्ठिर
atrāpyudāharantīmamitihāsaṃ purātanampituḥ putreṇa saṃvādaṃ tannibodha yudhiṣṭhira
Our plain-language meaning of this verse is waiting for scholar review.