  The specification, design, and assurance of safety encompasses various
concepts and best practices, subject of reuse in form of patterns. This work
summarizes applied research on such concepts and practices with a focus on the
last two decades and on the state-of-the-art of patterns in safety-critical
system design and assurance argumentation. We investigate several aspects of
such patterns, for example, where and when they are applied, their
characteristics and purposes, and how they are related. For each aspect, we
provide an overview of relevant studies and synthesize a taxonomy of first
principles underlying these patterns. Furthermore, we comment on how these
studies address known challenges and we discuss suggestions for further
research. Our findings disclose a lack of research on how patterns improve
system safety claims and, vice versa, on the decomposition of system safety
into separated local concerns, and on the impact of security on safety.
