AUTHOR=Sandner Philipp , Schulden Philipp M. TITLE=Speciality Grand Challenges: Blockchain JOURNAL=Frontiers in Blockchain VOLUME=2 YEAR=2019 URL=https://www.frontiersin.org/journals/blockchain/articles/10.3389/fbloc.2019.00001 DOI=10.3389/fbloc.2019.00001 ISSN=2624-7852