Constant (constant Anton Nieuwenhuys) ( 1920 - 2005 ) was a Dutch painter. Constant (constant Anton Nieuwenhuys) s works have been put up for auction numerous times, with realized prices surpassing estimated prices, varying from 1660 USD for Preliminary drawing for Casanova in 2002 to a remarkable record 336443.13 USD for TWEE VOGELS (Deux oiseaux), 1949 in 2007 , based on the size and medium of