What is the crossword answer for the clue: Cover letters?

SPF - a 3 letter word may be the answer you are looking for!

ISBN - a 4 letter word may be the answer you are looking for!

TITLE - a 5 letter word may be the answer you are looking for!

AKA - a 3 letter word may be the answer you are looking for!

Cover letters?

3 Character Answers:

AKA

SPF

4 Character Answers:

ISBN

5 Character Answers:

TITLE