Question: Who had more pseudonyms, Robert Ludlum or Clement Greenberg?

full_context: Document 1: Bourne (novel series): Bourne are a series of three novels by Robert Ludlum based on the fictional spy Jason Bourne. The series has since been further extended by Eric Van Lustbader after the death of Robert Ludlum.
Document 2: Woman VI: In 1953, Woman, a series of abstract works of art painted by Willem de Kooning, shocked the public who visited de Kooning’s third one-man show at the Sidney Janis Gallery in Manhattan. The last painting of this series, "Woman VI", is displayed at the Carnegie Museum of Art as part of the Postwar Abstraction collection since the 1955 Carnegie International Exhibition. Willem de Kooning is a pioneer of abstract expressionism in America. This painting is a good example of contemporary art’s transition from European traditional painting to abstract expressionism; "Woman" is considered de Kooning’s most famous series because it is significant to postwar history and social events, such as the American Feminist Movement in 1960s; de Kooning has a ventured impact on the issue of the representation of woman during 1950s through the abstract form; and, above all, Woman VI is an irreplaceable work of art for the Postwar Abstraction collection not only for its abstract form and brushwork techniques but because it still has the ability to create multiple interpretations with each viewing.
Document 3: De Kooning: An American Master: de Kooning: An American Master is a biography of Dutch American painter Willem de Kooning, a prominent figure in the American movement of abstract expressionism in the thirties and forties. Often compared to Jackson Pollock and Arshile Gorky, de Kooning was considered one of the more inspirational and influential artists of the 20th century. The book, which is the first comprehensive biography presenting both de Kooning's personal life and career, was written by authors by Mark Stevens and Annalyn Swan. In 2005, the book was honored with the 2005 Pulitzer Prize for Biography or Autobiography.
Document 4: Helen Frankenthaler: Helen Frankenthaler (December 12, 1928 – December 27, 2011) was an American abstract expressionist painter. She was a major contributor to the history of postwar American painting. Having exhibited her work for over six decades (early 1950s until 2011), she spanned several generations of abstract painters while continuing to produce vital and ever-changing new work. Frankenthaler began exhibiting her large-scale abstract expressionist paintings in contemporary museums and galleries in the early 1950s. She was included in the 1964 "Post-Painterly Abstraction" exhibition curated by Clement Greenberg that introduced a newer generation of abstract painting that came to be known as Color Field. Born in Manhattan, she was influenced by Greenberg, Hans Hofmann, and Jackson Pollock's paintings. Her work has been the subject of several retrospective exhibitions, including a 1989 retrospective at the Museum of Modern Art in New York City, and been exhibited worldwide since the 1950s. In 2001, she was awarded the National Medal of Arts.
Document 5: Robert Ludlum's The Bourne Conspiracy: Robert Ludlum's The Bourne Conspiracy (known as simply The Bourne Conspiracy) is a third-person action stealth video game developed by High Moon Studios and published by Sierra Entertainment for the PlayStation 3 and Xbox 360. The game expands upon Robert Ludlum's character Jason Bourne, and immerses the player in a cat and mouse style espionage action adventure. The game was released in North America on June 3, June 5 in Australia and June 27, 2008 in Europe.
Document 6: Robert Ludlum bibliography: Robert Ludlum (1927–2001) was an American author of twenty-seven novels between 1971 and 2006, the last being issued five years after his death. Of his twenty-seven novels, two were originally published under the pseudonym of Jonathan Ryder and another under the pseudonym of Michael Shepherd. Ludlum also created the "Covert-One" series, overseeing the first three novels with Gayle Lynds and Philip Shelby before his death. Following Ludlum's death, his estate has continued to publish novels under his name with eight authors having written a combined twenty-two novels under the Ludlum brand, a trademark inscription of "Robert Ludlum's" on every book (e.g. "Robert Ludlum's The Bourne Dominion"). Since 2007, publishing rights in the United States have been held by Grand Central Publishing, taking over from St. Martin's Press who held the rights from 2000 to 2006.
Document 7: Sidney Janis: Sidney Janis (July 8, 1896 – November 23, 1989) was a wealthy clothing manufacturer and art collector who opened an art gallery in New York in 1948. His gallery quickly gained prominence, for he not only exhibited the work of most of the emerging leaders of Abstract Expressionism, but also that of such important European artists as Pierre Bonnard, Paul Klee, Joan Miró, and Piet Mondrian. As the critic Clement Greenberg explained in a 1958 tribute to the dealer, Janis' exhibition practices had helped to establish the legitimacy of the Americans, for his policy "not only implied, it declared, that Jackson Pollock, Willem de Kooning, Franz Kline, Phillip Guston, Mark Rothko, and Robert Motherwell were to be judged by the same standards as Matisse and Picasso, without condescension, without making allowances." Greenberg observed that in the late 1940s "the real issue was whether ambitious artists could live in this country by what they did ambitiously. Sidney Janis helped as much as anyone to see that it was decided affirmatively."
Document 8: Bourne (film series): The Bourne films are a series of action spy thriller films based on the character Jason Bourne (Matt Damon), a CIA assassin suffering from extreme memory loss who must figure out who he is, created by author Robert Ludlum.
Document 9: Robert Coates (critic): Robert Myron Coates (April 6, 1897 – February 8, 1973) was an American writer and a long-term art critic for the "New Yorker". He coined the term "abstract expressionism" in 1946 in reference to the works of Arshile Gorky, Jackson Pollock and Willem de Kooning.
Document 10: The Bourne Supremacy: The Bourne Supremacy is the second Jason Bourne novel written by Robert Ludlum, first published in 1986. It is the sequel to Ludlum's bestseller "The Bourne Identity" (1980) and precedes Ludlum's final Bourne novel, "The Bourne Ultimatum" (1990).
Document 11: Jason Bourne: Jason Bourne ( ) is a fictional character created by novelist Robert Ludlum. Bourne is the antihero in a series of fourteen novels (to 2016) and subsequent film adaptations. He first appeared in the novel "The Bourne Identity" (1980), which was adapted for television in 1988. The novel was adapted in 2002 into a feature film under the same name and starred Matt Damon in the lead role.
Document 12: Tyler Green (journalist): Tyler Green is an award-winning art critic and historian. He produces and hosts The Modern Art Notes Podcast, a weekly digital audio program that features interviews with artists and art historians such as Richard Serra, Robert Irwin, Phyllida Barlow, Carl Andre, Sophie Calle, Vija Celmins, Mark Bradford, Julie Mehretu, Jo Ann Callis, and Shirin Neshat. Pulitzer Prize-winning art critic Sebastian Smee called The MAN Podcast "one of the great archives of the art of our time."
Document 13: Clement Greenberg: Clement Greenberg ( ), occasionally writing under the pseudonym K. Hardesh (January 16, 1909 – May 7, 1994), was an American essayist known mainly as an influential visual art critic closely associated with American Modern art of the mid-20th century. In particular, he is best remembered for his promotion of the abstract expressionist movement and was among the first published critics to praise the work of painter Jackson Pollock.
Document 14: The Bourne Identity (novel): The Bourne Identity is a 1980 spy fiction thriller by Robert Ludlum that tells the story of Jason Bourne, a man with remarkable survival abilities who suffers from retrograde amnesia, and must seek to discover his true identity. In the process, he must also reason out why several shadowy groups, a professional assassin, and the CIA want him dead. The story takes readers on an action-packed journey into a world of deceptions and conspiracies, offering a psychological portrait of Bourne, and giving them the chance to experience from his point of view the life-or-death decisions he makes as he seeks to piece together the dangerous puzzle of his missing past. It is the first novel of the original Bourne Trilogy, which also includes "The Bourne Supremacy" and "The Bourne Ultimatum".
Document 15: Robert Ludlum: Robert Ludlum (May 25, 1927 – March 12, 2001) was an American author of 27 thriller novels, best known as the creator of Jason Bourne from the original "The Bourne Trilogy" series. The number of copies of his books in print is estimated between 290 million and 500 million. They have been published in 33 languages and 40 countries. Ludlum also published books under the pseudonyms Jonathan Ryder and Michael Shepherd.
ground_truth: Robert Ludlum