Krall--type Orthogonal Polynomials in several variables
  For a bilinear form obtained by adding a Dirac mass to a positive definite moment functional in several variables, explicit formulas of orthogonal polynomials are derived from the orthogonal polynomials associated with the moment functional. Explicit formula for the reproducing kernel is also derived and used to establish certain inequalities for classical orthogonal polynomials. 
Lidia Fernandez, Teresa E. Perez, Miguel A. Pinar, Yuan Xu