Linked from
The 63 pages that link to Beta decay, each with the reason it gives.
Down quarkRelated: In beta-minus decay, a neutron’s down quark changes into an up quark.
Tritiated waterRelated: Tritium in water decays by emitting a low-energy electron.
Carbon isotopesRelated: Carbon-14 decays by converting a neutron into a proton.
Caesium-137Related: Caesium-137 decays by emitting an electron, becoming metastable barium-137.
Free neutron decayNarrower topic: Free neutron decay is beta-minus decay without a nucleus.