A Leonardo da Vinci expert says the claim is worth further research . The artist was born in Florence and died at age 88 in Italy. The Mona Lisa Foundation exists solely to research this one painting .
A Leonardo da Vinci expert says the claim is worth further research . Swiss foundation unveils what it claims is a predecessor to `` Mona Lisa '' An Oxford University professor cast doubt on its authenticity . The Mona Lisa Foundation exists solely to research this one painting .