Contributors, builders and testers include Eric Lombrozo (cross-compilation), Tim Hughes (MSVC compilation & Dagger testing), Alex Leverington (Clang & Mac building), Marko Simovic (CI) and several others.
Ethereum is based on a design in an original whitepaper by Vitalik Buterin. This implementation is based on the formal specification of a refinement of that idea detailed in the 'yellow paper' by Gavin Wood. Contributors, builders and testers include Alex Leverington (Clang & Mac building, client multiplexing), Tim Hughes (MSVC compilation & Dagger testing), Caktux (ongoing CI), Christoph Jentzsch (tests), Christian Reissweiner (Solidity), Marek Kotewicz (external JS & JSON-RPC), Eric Lombrozo (MinGW32 cross-compilation), Marko Simovic (original CI), and several others.