@InCollection{hehl2023coefficientcontrolvariationalinequalities,
      title={Coefficient Control of Variational Inequalities}, 
      author={Andreas Hehl and Denis Khimin and Ira Neitzel and Nicolai Simon and Thomas Wick and Winnifried Wollner},
      year={2023},     
  booktitle	= {to appear},
  annote	= {series,}
}