Columbia subject headings:
Abbreviations.
Acronyms.
Associations, institutions, etc.--Abbreviations.
Portuguese language--Acronyms.
Harvard subject headings:
Abbreviations, Portuguese--Dictionaries.
Abbreviations.
Acronyms.
Portuguese language--Acronyms--Dictionaries.
Princeton subject headings:
Abbreviations.
Acronyms.
Aeronautics--Abbreviations.
Signs and symbols.