Look at the following panel from Amazing Spider-Man #197:
Pay attention to the Kingpin's first speech bubble:
Must I repeat Samuel Clemens' oft-quoted line?
Why doesn't he repeat the often quoted line?
a. He does, it is in the next speech bubble at the bottom of the panel.
b. The author feels that everyone should know the line in question and so it doesn't need to be repeated.
c. There is not enough room in the panel for the quote.
d. The quote was copyrighted and could not be re-printed without permission from Samuel Clemens.
Scroll down for the answer.
a. is incorrect.
b. is correct. Samuel Clemens is the real name of Mark Twain. Many of Twain's quotes are well known and usually do not have to be repeated completely for people to recognize it.
c. is incorrect.
d. is incorrect. No copyright is needed to quote someone as long as you acknowledge that it is someone else's words.