The claim that the Earth is visible from the International Space Station is a matter of everyday physical fact and direct observation, requiring no special citation, though instrumentation studies confirm it.
The claim is trivially true by direct observation and orbital mechanics: the ISS orbits Earth at roughly 400 km altitude, facing the planet, and is used constantly to observe and photograph Earth. Paper [1] directly confirms this by discussing telescope observations of the Earth from the ISS. Therefore, it is common knowledge, and the citation is supplied as supplementary verification.