CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS (Parts 50–99) > PART 91—CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES > SUBPART D—Emission Test Equipment Provisions (§91.301 to §91.329) > 91.303—Acronyms and abbreviations.