@article {SetLucLie15a,
    AUTHOR = {S{\`e}te, Olivier and Luce, Robert and Liesen, J{\"o}rg},
     TITLE = {Perturbing rational harmonic functions by poles},
   JOURNAL = {Comput. Methods Funct. Theory},
  FJOURNAL = {Computational Methods and Function Theory},
    VOLUME = {15},
      YEAR = {2015},
    NUMBER = {1},
     PAGES = {9--35},
}