If you search for dog proof trap they'll come up. They look like this:
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There are different variations of it. The Duke shown above is triggered when they reach and and pull. Ztrap is push or pull. Arm it, stake it down, put some marshmallows inside under the trigger bar and a couple right outside the mouth of the trap. They'll eat the ones right out front and then reach to grab the marshmallows inside, and pull the trigger.
They're cheap and effective. You could use different baits, but marshmallows are cheap and don't stink.