scattering - Evidence for standard model description of neutrons

as I don't know too much about experiments I have the following question concerning the evidence about the quark constituents in neutrons.

After a quick google investigation I found some sentences like "In 1968, at the Stanford Linear Accelerator Center (SLAC), electrons were fired at protons and neutrons in atomic nuclei." (Wikipedia article on deep inelastic scattering). However, the referred sources are always only dealing with deep inelastic proton scattering experiments.

Hence, the following question: Is there any evidence (any experiment) that tests whether neutrons are composed the way the standard model describes it? (ie neutron = {up, down, down} etc)

Thanks in advance for your insights!!

Best, Alex