The claim that telescopes increase angular magnification by gathering light over a wide area and compressing it into a narrower bundle of rays entering the eye is a fundamental geometric and optical definition of how optical telescopes work, requiring no external citation.
The provided papers discuss various unrelated topics such as Mars rover instrumentation, AR waveguides, biomedical nanofiber mats, telescope coronagraphs, eye models, intraocular lenses, metalenses, lensless cameras, muscle monitoring devices, guided endodontics, adaptive optics ophthalmoscopes, and cotton fiber microscopy. None of these papers specifically study or contest the basic optical principle of telescope magnification. However, the claim itself is a matter of elementary optical physics and everyday definition (common knowledge), so no citation is needed.