Question:  Jeff Mangum and Spider One, are singers, of which nationality?

Context articles: Orange Twin Field Works: Volume I
Spider One
Live at Jittery Joe's
Korena Pang
You've Passed/Where You'll Find Me Now
Anyone for Doomsday?
Jeff Mangum
Major Organ and the Adding Machine
Everything Is (EP)
The Olivia Tremor Control

Orange Twin Field Works: Volume I is a collection of Bulgarian folk music released by Jeff Mangum, of Neutral Milk Hotel.
 The album contains one track, a little over a half-hour of different segments from a single festival.
Michael David Cummings (born August 25, 1968), better known as Spider One, is an American singer, songwriter, rapper, record producer, and director.
 He is the founder and only consistent member of the nu metal band Powerman 5000 and the owner of Megatronic Records.
 He created the horror/black comedy mockumentary series "Death Valley", which aired on MTV for one season in 2011.
Live at Jittery Joe's is an album released in 2001 by Jeff Mangum of Neutral Milk Hotel to battle the high prices of bootlegs on eBay.
 Filmmaker Lance Bangs recorded it at the Athens, GA venue Jittery Joe's on March 7, 1997 during a live solo performance; this location was the original Jittery Joe's at 243 W. Washington St., not one of the current locations.
 Jeff had not prepared a set list, so some of the songs were chosen by the audience.
 A noisy child can be heard throughout the performance (most notably during "Oh Comely").
Korena Pang was a name used by Jeff Mangum for his sound collage work, which he debuted during his 2002 show on New Jersey radio station WFMU.
 The name first appeared in the liner notes to the 1996 Neutral Milk Hotel album "On Avery Island", and has been used interchangeably with another pseudonym, Alfred Snouts.
 Mangum described the process of constructing sound collage pieces during a rare interview with Pitchfork the same year:
You've Passed/Where You'll Find Me Now is the third single by American psychedelic folk band Neutral Milk Hotel, released as part of their "Walking Wall of Words" compilation package on December 12, 2011.
 The single contains alternative versions of "You've Passed" and "Where You'll Find Me Now", which were both songs on the band's 1996 album "On Avery Island".
 Both songs were written by and are played by Jeff Mangum.
 He recorded both tracks at his father's house in Ruston, Louisiana in December 1994 on his four-track cassette tape.
 Both tracks, in comparison to their "On Avery Island" counterparts, are more distorted and longer.
 The album was engineered by Craig Morris and mastered by friend and long-time collaborator Robert Schneider.
Anyone for Doomsday?
 is the third full-length album by Powerman 5000, and was originally slated as the follow-up to "Tonight the Stars Revolt!
".
 It was pulled by PM5K frontman Spider One two weeks before the release date.
 Due to being too similar to previous work, the album was originally intended to merely be delayed and revamped.
 However, during this time conflicts began to arise causing longtime members Dorian 27 (Dorian Heartsong) and Al3 (Allen Pahanish) to leave the band.
 As a result, the album was scrapped due to Spider's unwillingness to release an album of half new members and half old.
 The album was available for a while on Powerman 5000's official website through Spider One's record label, Megatronic Records.
 The promotional copies featured artwork that was different from the copies available on the website.
 The album however was taken down due to legal reasons.
 The album is now available in full on Spotify.
 The physical copy of the album has become a collector's item.
Jeff Mangum (born October 24, 1970) is an American singer, songwriter, and multi-instrumentalist, best known for his work as the lyricist, vocalist and guitarist of the band Neutral Milk Hotel, as well as being one of the cofounders of The Elephant 6 Recording Company.
 He is best known for his complex, lyrically dense songwriting, apparent on the critically lauded album "In the Aeroplane Over the Sea".
Major Organ and the Adding Machine is an Elephant 6 supergroup led by the elusive and possibly fictional Major Organ.
 The liner notes of the band's debut album, Major Organ and the Adding Machine, leave it a mystery as to who is officially featured.
 When performing live on the Holiday Surprise Tour, the members of the band wore paper masks to maintain their anonymity.
 It is believed that the main contributors are Jeff Mangum, Julian Koster, Robert Schneider, and Kevin Barnes, whose vocals are most obviously present on the album, but a number of other Elephant 6 musicians are believed to have contributed too, including members of The Olivia Tremor Control, Elf Power, and Of Montreal.
Everything Is was the first recording mass-released by Neutral Milk Hotel, at that point still largely an outlet for the songwriting of Jeff Mangum instead of a fully formed band.
 The recording was originally the second release on the fledgling Seattle label Cher Doll Records in 1994.
 The label in the form of a 7", with "Everything Is" as the A side, and "Snow Song, Pt. 1" as the B side.
 The first 50 7"s pressed also featured different artwork, with each sleeve being personally xeroxed by Mangum.
 The Cher Doll edition is now out of print.
The Olivia Tremor Control is an American rock band that was prominent in the mid-to-late 1990s.
 It was, along with The Apples in Stereo and Neutral Milk Hotel, one of the three original projects of The Elephant 6 Recording Company.
 The band was founded by the remnants of the group Synthetic Flying Machine (Jeff Mangum, Bill Doss, and Will Cullen Hart) in 1994.
 The band went on hiatus in early 2000, and later reformed in 2009.