Media type: E-Article Title: On Dirac operators in $$\mathbb {R}^3$$ R 3 with electrostatic and Lorentz scalar $$\delta $$ δ -shell interactions Contributor: Behrndt, Jussi; Exner, Pavel; Holzmann, Markus; Lotoreichik, Vladimir imprint: Springer Science and Business Media LLC, 2019 Published in: Quantum Studies: Mathematics and Foundations Language: English DOI: 10.1007/s40509-019-00186-6 ISSN: 2196-5609; 2196-5617 Origination: Footnote: