A proposal may be introduced as a bill, a joint resolution, a concurrent resolution, or a simple resolution. Legislators use joint resolutions to propose a constitutional amendment. Concurrent resolutions (passed by both houses) and simple resolutions (passed by only one house) do not have the force of law. Instead, they serve to express the opinion of approving house of houses, or to regulate procedure. Article 5 Section 33 of the Oklahoma Constitution requires bills for raising revenue to originate in the Oklahoma House.