https://www.fmf.uni-lj.si/sl/obvestila/obvestilo/32421/mitja-nedic-the-convex-combination-problem-for-herglotz-nevanlinna-functions/
Mitja Nedić: The convex combination problem for Herglotz-Nevanlinna functions • FMF
convex combinationmitjaproblemherglotznevanlinna