There are a few broken links: - https://openigtlink.org/about - [specification of OpenIGTLink](https://openigtlink.org/spec) - [C/C++ library](https://openigtlink.org/sdk) - [The specification of the OpenIGTLink protocol](https://openigtlink.org/spec) - https://openigtlink.org/developers/spec - [Release 2.0](https://openigtlink.org/developers/protocols/v2_index.html)
