It is so good, after so many years of public indifference, even hostility towards Vincent and his work, to feel towards the end of my life that the battle is won.'JO VAN GOGH-BONGER TO GUSTAVE COQUIOT, 1922'It is a sacrifice for the sake of Vincent's glory.'JO VAN GOGH-BONGER ON THE SALE OF 'THE SUNFLOWERS' TO THE NATIONAL GALLERY, UK, 1924Little known but no less influential, Jo van Gogh-Bonger was sister-in-law of Vincent van Gogh, wife of his brother, Theo. When the brothe