Preface: Dedicated to the memory of Zoltán Ésik (1951–2016)
Crossref DOI link: https://doi.org/10.1007/s00500-018-3027-y
Published Online: 2018-01-23
Published Print: 2018-02
Update policy: https://doi.org/10.1007/springer_crossmark_policy
Droste, Manfred
Larsen, Kim G.
License valid from 2018-01-23