Refrain from using " ", italics, ( ), and underlined words in an academic paper, as far as possible.  In academic writing, you would rather explain what you mean, instead of the use of " ", italics, ( ), and underlined to accentuate phrases. 14 punctuation marks are commonly used in English grammar.  They are the period, question mark, exclamation point, comma, semicolon, colon, dash, hyphen, parentheses, brackets, braces, apostrophe, quotation marks, and ellipsis.  It is more correct in academic writing to write out everything you state, e.g. "The company is a South African Part 121 (large aircraft operator) and Part 135 (small aircraft operator) company, holding South African Civil Aviation Authority (SACAA) issued AOCs (Air Operator Certificates) in both of these categories." vs. "Air-Wing-X is a South African Part 121 and Part 135 organisation.  Part 121 regulates operating requirements for large aircraft operators, whereas Part 135 regulates operating requirements for small aircraft operators.  The South African Civil Aviation Authority (SACAA) is responsible for the issuing and good standing of Air Operator Certificates (AOC) to aircraft operators.  Air-Wing-X is a SACAA-certified air operator with good standing in Parts 121 and 135."