Industry adoption of the Internet of Things: A constrained application protocol survey. - Christian Lerche; Klaus Hartke; Matthias Kovatsch (ETFA, 2012)

The Constrained Application Protocol (CoAP). - Zach Shelby; Klaus Hartke; Carsten Bormann (RFC, 2014)

Observing Resources in the Constrained Application Protocol (CoAP). - Klaus Hartke (RFC, 2015)

CoAP (Constrained Application Protocol) over TCP, TLS, and WebSockets. - Carsten Bormann; Simon Lemay; Hannes Tschofenig; Klaus Hartke; Bilhanan Silverajan; Brian Raymor (RFC, 2018)

Multipart Content-Format for the Constrained Application Protocol (CoAP). - Thomas Fossati; Klaus Hartke; Carsten Bormann (RFC, 2020)

Operating large-scale IoT systems through declarative configuration APIs. - Rajat Kandoi; Klaus Hartke (DAI-SNAC@CoNEXT, 2021)

Extended Tokens and Stateless Clients in the Constrained Application Protocol (CoAP). - Klaus Hartke; Michael C. Richardson (RFC, 2021)