Software reference implementations of ICT standards have an important role for verifying that a standard is implementable, supporting interoperability testing among other implementations, and providing feedback to the standard development process. Providing reference implementations and widely used implementations of a standard as Open Source Software also promotes wide deployment in software systems, avoidance of different lock-in effects, interoperability, and longevity of systems and associated digital assets. In this paper results are reported on the availability of reference implementations and widely deployed implementations provided as Open Source Software for standards issued by different standards setting organisations. Specifically, findings draw from observations and analyses related to software implementations for identified standards issued by ETSI, IEC, IEEE, IETF, ISO, ITU-T, OASIS, and W3C.