Running on the Sun: The Badwater 135 is a 2000 documentary film directed by Mel Stuart.
 The film follows athletes as they run 135 miles in the 1999 Badwater Ultramarathon, starting in California's Death Valley and ending at Whitney Portal, the trailhead to Mount Whitney.
Explore was a 1980s PBS TV show based upon the film footage filmed by explorer Douchan Gersi over the previous 20 years.
 The show was hosted by popular actor James Coburn.
Four Days in November is a 1964 American documentary film directed by Mel Stuart about the assassination of John F. Kennedy.
 It was nominated for an Academy Award for Best Documentary Feature.
Milton "Mel" Stewart (September 19, 1929 – February 24, 2002) was an American character actor, television director, and musician who appeared in numerous films and television shows from the 1960s to the 1990s.
 He is best known for playing Henry Jefferson on the popular television series "All in the Family" and for playing section chief Billy Melrose on the television series "Scarecrow and Mrs. King".
 Stewart is sometimes credited as Melvin Stewart or Mel Stuart.
Mel Stuart (born Stuart Solomon; September 2, 1928 – August 9, 2012) was an American film director and producer, who often worked with producer David L. Wolper, whose production firm he worked for 17 years, before going freelance.
The Triangle Factory Fire Scandal is a 1979 American made-for-television drama film starring David Dukes, Tovah Feldshuh, Lauren Frost, Stacey Nelkin and Ted Wass.
 It was directed by Mel Stuart and premiered on NBC on January 30, 1979.
Willy Wonka & the Chocolate Factory is a 1971 American musical fantasy film directed by Mel Stuart, and starring Gene Wilder as Willy Wonka.
 It is an adaptation of the 1964 novel "Charlie and the Chocolate Factory" by Roald Dahl.
 Dahl was credited with writing the film's screenplay; however, David Seltzer, who went uncredited in the film, was brought in to re-work Dahl's screenplay against his wishes, making major changes to the ending and adding musical numbers.
 These changes and other decisions made by the director led Dahl to disown the film.
One Is a Lonely Number (also known as Two Is a Happy Number) is a 1972 American drama film directed by Mel Stuart and starring Trish Van Devere, Janet Leigh and Melvyn Douglas.
 The screenplay, based upon the short story "The Good Humor Man" by Rebecca Morris, was written by David Seltzer.
Wattstax was a benefit concert organized by Stax Records to commemorate the seventh anniversary of the 1965 riots in the African-American community of Watts, Los Angeles.
 The concert took place at the Los Angeles Memorial Coliseum on August 20, 1972.
 The concert's performers included all of Stax's prominent artists at the time.
 The genres of the songs performed included soul, gospel, R&B, blues, funk, and jazz.
 Months after the festival, Stax released a double LP of the concert's highlights titled "Wattstax: The Living Word".
 The concert was filmed by David L. Wolper's film crew and was made into the 1973 film titled, "Wattstax".
 The film was directed by Mel Stuart and nominated for a Golden Globe award for Best Documentary Film in 1974.
Douchan Gersi (1947–2015) was a Slovak-born, Belgium-raised, Bali-based adventurer, documentary filmmaker, author and actor, producer/star with actor James Coburn of "Explore", a PBS mini-series.
 He is the author of numerous books including "Faces in the Smoke: An Eyewitness Experience of Voodoo, Shamanism, Psychic Healing, and Other Amazing Human Powers" and "Explorer".

Question: Are both directors Mel Stuart and Douchan Gersi American?
Answer: no