The fact that quantum degeneracy pressure prevents matter from collapsing into an infinitely dense point in white dwarfs and neutron stars is standard textbook physics and well-established scientific knowledge, requiring no citation.
The claim states a fundamental, well-known principle of stellar physics (electron and neutron degeneracy pressure supporting compact objects against gravitational collapse). Because this is a matter of established textbook physics and common knowledge, no citations are needed, so no papers are attached.