Question: What nationality are both Gerald Green and Allen Drury?

Context paragraphs:
Preserve and Protect: Preserve and Protect is a 1968 political novel written by Allen Drury.  It is the third sequel to "Advise and Consent", for which Drury was awarded the Pulitzer Prize for Fiction in 1960, and is followed by two alternate sequels of its own, "Come Nineveh, Come Tyre" (1973) and "The Promise of Joy" (1975).

A Thing of State: A Thing of State is a 1995 political novel by Allen Drury which follows the U.S. State Department's response to a crisis in the Middle East.  It is a standalone work set in a different fictional timeline from Drury's 1959 novel "Advise and Consent", which earned him a Pulitzer Prize for Fiction.

Allen Drury's University series: Allen Drury's "University" series is a trio of novels written by political novelist Allen Drury between 1990 and 1998, which follow a group of university fraternity brothers for a span of over 60 years from 1938 to 2001.  Drury graduated from Stanford University in 1939, and his experiences there provided the basis for the series.  The novels are set in a different fictional timeline from Drury's 1959 novel "Advise and Consent", which earned him a Pulitzer Prize for Fiction.

Mark Coffin, U.S.S.: Mark Coffin U.S.S. is a 1979 political novel by Allen Drury which follows the titular young U.S. Senator as he navigates Washington politics.  It is set in a different fictional timeline from Drury's 1959 novel "Advise and Consent", which earned him a Pulitzer Prize for Fiction.

Allen Drury: Allen Stuart Drury (September 2, 1918 – September 2, 1998) was an American novelist.  He wrote the 1959 novel "Advise and Consent", for which he won the Pulitzer Prize for Fiction in 1960.

Anna Hastings: Anna Hastings: The Story of a Washington Newspaperperson is a 1977 political novel by Allen Drury which follows the titular reporter as she climbs her way to the top of the Washington media elite.  It is set in a different fictional timeline from Drury's 1959 novel "Advise and Consent", which earned him a Pulitzer Prize for Fiction.

A Shade of Difference: A Shade of Difference (ISBN  ) is a 1962 political novel written by Allen Drury.  It is the first sequel to "Advise and Consent", for which Drury was awarded the Pulitzer Prize for Fiction in 1960, and was followed in 1966 by "Capable of Honor".

Capable of Honor: Capable of Honor is a 1966 political novel written by Allen Drury.  It is the second sequel to "Advise and Consent", for which Drury was awarded the Pulitzer Prize for Fiction in 1960.

Decision (novel): Decision is a 1983 political novel by Allen Drury which follows a newly appointed Supreme Court Justice as he is faced with the most difficult decision of his life.  It is a standalone work set in a different fictional timeline from Drury's 1959 novel "Advise and Consent", which earned him a Pulitzer Prize for Fiction.

Gerald Green (author): Gerald Green (April 8, 1922 – August 29, 2006) was an American author, journalist, and television writer.

Supporting paragraphs: Gerald Green (author) Allen Drury
Answer: American