Question: Harry Turtledove and E. L. Doctorow, are of which nationality?

Context paragraphs:
The Great War: American Front: The Great War: American Front is the first alternate history novel in the Great War trilogy by Harry Turtledove.  It is the second part of Turtledove's Southern Victory series of novels.  It takes the Southern Victory Series from 1914 to 1915.

The Man with the Iron Heart: The Man with the Iron Heart is an alternate history novel by Harry Turtledove.  Published in 2008, it takes as its premise the survival by Reinhard Heydrich of his 1942 assassination in Czechoslovakia and his subsequent leadership of the postwar "Werwolf" insurgency in occupied Germany, which Turtledove depicts as growing into a far more formidable force than was the case historically.

Harry Turtledove: Harry Norman Turtledove (born June 14, 1949) is an American novelist, best known for his work in the genres of alternate history, historical fiction, fantasy, and science fiction.

American Empire: The Center Cannot Hold: American Empire: The Center Cannot Hold is the second book in the "American Empire" alternate history series by Harry Turtledove.  It takes place during the period of the Roaring Twenties and the Great Depression (specifically from 1924 to March 4, 1934).  During this era in Turtledove's Southern Victory world, the Confederate States of America, stretching from Sonora to Virginia, is led by Whigs (with the fascist Freedom Party gaining more and more power) while the United States of America (which has been occupying Canada, Newfoundland, the Bahamas, Bermuda, and the Sandwich Islands) is controlled by Socialists.

Videssos cycle: The Videssos cycle (sometimes also referred to as the Lost Legion series) is a fantasy novel series by Harry Turtledove and set in the Videssos fictional universe.  Turtledove uses his knowledge of Byzantine Empire history and military experience extensively within the story.

Give Me Back My Legions!: Give Me Back My Legions!  is a 2009 historical novel by Harry Turtledove.  While Turtledove is mainly known for alternate history novels, this novel is a historical novel, in which the real-life events leading up to the Battle of the Teutoburg Forest, as well as the battle itself, are re-created.

The Last Article: "The Last Article" (1988), is an alternate history short story by Harry Turtledove.  The story describes a Nazi invasion of India and the reaction of the Germans to the nonviolent resistance and pacifism of Mohandas Gandhi and his followers.  This story was later reprinted in Turtledove's short-story collection "Kaleidoscope" in 1990, and the variety showcase "The Best Military Science Fiction of the Twentieth Century" in 2001.

E. L. Doctorow: Edgar Lawrence "E. L." Doctorow (January 6, 1931 – July 21, 2015) was an American novelist, editor, and professor, best known internationally for his works of historical fiction.  He has been described as one of the most important American novelists of the 20th century.

Worldwar series: The Worldwar series is the fan name given to a series of alternate history science fiction novels by Harry Turtledove.  Its premise is an alien invasion of Earth during World War II, and includes Turtledove's "Worldwar" tetralogy; as well as the "Colonization" trilogy; and the novel Homeward Bound.  The series' time-span ranges from 1942–2031.  The early series was nominated for a Sidewise Award for Alternate History in 1996.

The Road Not Taken (short story): "The Road Not Taken" is a short story by Harry Turtledove, set in 2039, in which he presents a fictitious account of a first encounter between humanity and an alien race, the Roxolani.  "Herbig-Haro" is another short story by Turtledove, which is the sequel to this one.

Supporting paragraphs: Harry Turtledove E. L. Doctorow
Answer: American