Stationary loop currents (steady currents in closed paths) produce static magnetic fields and do not undergo time-varying acceleration that gives rise to electromagnetic radiation, which is a fundamental principle of classical electrodynamics.
The claim states a foundational principle of classical electrodynamics: steady, time-independent (stationary) currents do not radiate electromagnetic waves, as radiation requires time-varying charge or current distributions (accelerated charges). This is a textbook fact of physics and common knowledge, requiring no specific citation of papers for validation.