I believe the article refers specifically to Whitted ray tracing when referring to 'ray-tracing' as opposed to distribution ray tracing or path tracing. POV-ra

I believe the article refers specifically to Whitted ray tracing when referring to 'ray-tracing' as opposed to distribution ray tracing or path tracing. POV-ray supports all kind of ray tracing and path tracing techniques, not just Whitted RT.