Digital Contact Tracing Service: An improved decentralized design for privacy and effectiveness. - Kilian Holzapfel; Martina Karl; Linus Lotz; Georg Carle; Christian Djeffal; Christian Fruck; Christian Haack; Dirk Heckmann; Philipp H. Kindt; Michael Köppl; Patrick Krause; Lolian Shtembari; et al. (CoRR, 2020)