Question: Are novelists Walter Van Tilburg Clark and Billie Letts both American? 

full_context: Document 1: Jincy Willett: Jincy Willett is an author and writing teacher currently living in San Diego, California. She has written short pieces for various anthologies and periodicals including the Winter 2006 issue of "Timothy McSweeney's Quarterly Concern" and "Children Playing Before a Statue of Hercules". Her first book, a collection of short stories called "Jenny and the Jaws of Life", was initially published in 1987 to critical acclaim but smaller-than-expected sales. The public admiration of Willett's writing expressed by David Sedaris, however, had the book in reprint in 2002, garnering praise from critics and public alike.
Document 2: The Ox-Bow Incident (novel): The Ox-Bow Incident is a 1940 western novel by Walter Van Tilburg Clark in which two drifters are drawn into a lynch mob to find and hang three men presumed to be rustlers and the killers of a local man.
Document 3: Betty Louise Bell: Betty Louise Bell was born on November 23, 1949. She is a scholar and fiction writer of Cherokee ancestry. Bell is a former director of the Native American Studies Program and former assistant professor of American culture, English, and Women's Studies at the University of Michigan. Her areas of scholarly interest include Native American literature, Women's Studies, nineteenth-century American literature, and creative writing. She earned her PhD in 1985 from Ohio State University. Her first novel "Faces in the Moon" was published in 1994 and received favorable reviews. In addition, Bell has published critical articles on Native American Literature that emphasize the political and personal aspects of Native American identity.
Document 4: A Lesson Before Dying: A Lesson Before Dying Is Ernest J. Gaines' eighth novel, published in 1993. While it is a fictional work, it is loosely based on the true story of Willie Francis, a young Black man sentenced to death by the electric chair twice in Louisiana, in 1945 and 1947.
Document 5: Billie Letts: Billie Dean Letts (née Gipson; May 30, 1938 – August 2, 2014) was an American novelist and educator. She was a professor at Southeastern Oklahoma State University.
Document 6: Lexie Dean Robertson: Lexie Dean Robertson (July 25, 1893 – February 16, 1954) was a teacher and award-winning Poet Laureate of Texas from 1939 to 1941. She grew up in Canton, Texas, the daughter of teachers, and married a fellow student at North Texas State Normal College (today the University of North Texas), J. F. Robertson, in 1911. The couple settled in Rising Star in 1920. Robertson was the first native-born Texan to hold the position of Poet Laureate of Texas; among the publications which featured her work were "Kaleidograph", "Southwest Review", "Holland's Magazine", "Country Gentleman", "Good Housekeeping", and "Ladies' Home Journal".
Document 7: Louise Gopher: Louise Jones Gopher is the second Seminole (after Billy Cypress) and first woman from the Seminole tribe of Florida to earn a bachelor's degree. Gopher, a former director of education for the Seminole Tribe of Florida of Florida, was the first female Seminole to earn a bachelor's degree when she graduated from Florida Atlantic University in 1970. Born May 25, 1945 in a chickee at a tribal camp in Fort Pierce, Jones spoke no English when she entered school at age 6. Because they were considered neither black nor white, none of the segregated schools of the day would willingly take her as a student, but at the pleading of her father (who spoke, read, nor wrote any English), Lucie County Schools Superintendent Ben L. Bryan chose to allow her to enroll in the Fairlawn School. In 2014, she was granted an honorary Doctorate of Humane Letters from Florida State University. She is the third Seminole to receive an honorary degree from FSU, after Betty Mae Tiger Jumper (Doctorate of Humane Letters) and Jim Shore (Doctor of Laws). The "Palm Beach Post" named her one of the most 100 influential people in Florida in the 20th century.
Document 8: William Bizzell: William Bennett Bizzell (October 14, 1876 – May 13, 1944) was the president of three American higher education institutions. He was the fifth president of the University of Oklahoma, the president of Agricultural and Mechanical College of Texas (now Texas A&M University), and the president of the College of Industrial Arts (now Texas Woman's University).
Document 9: The Watchful Gods and Other Stories: The Watchful Gods and Other Stories is a collection of short stories by Walter Van Tilburg Clark published in 1950. It brings together eight stories and one novella (the title story). Three of the stories had already appeared in the annual anthology of O. Henry Award-winning stories, most notably "The Wind and the Snow of Winter" which was selected by that anthology, in 1945, as their "first-place winner." Since this book's publication, two other stories have remained notable: "The Portable Phonograph" and "Hook" have both been widely anthologized since they were published.
Document 10: Track of the Cat: Track of the Cat is a 1954 film directed by William A. Wellman and starring Robert Mitchum and Teresa Wright. The film is based on a 1949 adventure novel of the same name by Walter Van Tilburg Clark. This was Wellman's second adaptation of a Clark novel, the first being "The Ox-Bow Incident". "Track of the Cat" was produced by John Wayne and Robert Fellows for their Wayne/Fellows production company.
Document 11: The City of Trembling Leaves: The City of Trembling Leaves (1945) is a novel in the semi-autobiographical genre, by Walter Van Tilburg Clark. The novel is a series of parallel narratives detailing the lives and work of a group of redacted characters named Tim Hazard, Lawrence Black, Mary Turner, Rachel Wells, Marjory Hale, "Walt", (the narrator) and assorted other side-characters.
Document 12: Louis L'Amour: Louis Dearborn L'Amour ( ; March 22 1908 –June 10 1988) was an American novelist and short story writer. His books consisted primarily of Western novels (though he called his work 'frontier stories'); however, he also wrote historical fiction ("The Walking Drum"), science fiction ("The Haunted Mesa"), non-fiction ("Frontier"), as well as poetry and short-story collections. Many of his stories were made into films and John Wayne once made the dubious assertion that L'Amour was the most interesting man in the world. L'Amour's books remain popular and most have gone through multiple printings. At the time of his death almost all of his 105 existing works (89 novels, 14 short-story collections, and two full-length works of nonfiction) were still in print, and he was considered "one of the world's most popular writers".
Document 13: Wallace Stegner: Wallace Earle Stegner (February 18, 1909 – April 13, 1993) was an American novelist, short story writer, environmentalist, and historian, often called "The Dean of Western Writers". He won the Pulitzer Prize in 1972 and the U.S. National Book Award in 1977.
Document 14: Where the Heart Is (novel): Where the Heart Is is a 1995 novel by Billie Letts. It was chosen as an Oprah's Book Club selection in December 1998. A 2000 film of the same name was directed by Matt Williams, starring Natalie Portman, Ashley Judd and Stockard Channing.
Document 15: Walter Van Tilburg Clark: Walter Van Tilburg Clark (August 3, 1909 – November 10, 1971) was an American novelist, short story writer, and educator. He ranks as one of Nevada's most distinguished literary figures of the 20th century, and was the first inductee into the 'Nevada Writers Hall of Fame' in 1988. Two of his novels, "The Ox-Bow Incident" and "The Track of the Cat," were made into films. As a writer, Clark taught himself to use the familiar materials of the western saga to explore the human psyche and to raise deep philosophical issues.
ground_truth: yes