Early Giithaa sculptures

[Ashish Chandra]

N.Ganesan wrote :

  Some guy/s living in say, 2nd century AD (or say, 4th century AD?)
  who is well-versed on YogasUtras and UpaniSads might
  have authored GItA and placed it in MahabhArata.

  This could be a reaction to bhakti-like phenomenon
  in Mahayana and Jainism.

  These queries can be settled, (given that Krishna as a
  charioteer or advisor to Arjuna appear very late,
  post-14th centuy AD in art.) by pointing out GItA quotes
  in other Samskrit or other language texts, whose
  approximate dates we know.

  Hence, what are the earlier Giitaa citations in other Indian
  texts? Before Sankara.

  Regards,
  N. Ganesan

I believe I have read somewhere, I think it was in introduction to
Sankara's Gita Bhashya (I am not sure of the translator - Swami Panavananda
???) that the BG is placed as far back as 3102 BC which was the date for
the Mahabharata war and the beginning of Kali Yuga. I believe there are
several references to Vasudeva (Krishna) in various Vedic scriptures. Also,
several verses in BG resemble verses in the Upanisads. Which came first ?
Can this be determined ?

Thanks
Ashish