BOSTON (AP) -- When Gaylord Johnson Jr. was struggling with a term paper at Phillips Academy in Andover, Mass., he figured he'd ask for help from someone who knew the material best: Ernest Hemingway. "I've read a couple of the Nick Adams stories and have also read critical material on the same," Johnson wrote in a letter to Hemingway in 1956, referring to one of Hemingway's most famous characters. "I am, however, not quite satisfied with all I've read, and I wondered if you would write me and tell me just what you think of Nick Adams." Johnson's letter, along with more than 3,000 other documents from Hemingway's time in Cuba, was previously tucked away in the basement of Hemingway's estate at Finca Vigia, unseen by scholars and researchers. Now, thanks to an agreement between U.S. Rep James McGovern, D-Mass., and the Cuban government, copies of those writings are at the John F. Kennedy Library. The archival replicas include corrected proofs of "The Old Man and the Sea," a movie script based on the novel, an alternate ending to "For Whom the Bell Tolls" and thousands of letters, with correspondence from authors Sinclair Lewis and John Dos Passos and actress Ingrid Bergman. The documents were previewed Thursday and will likely be available to researchers in late spring. McGovern, museum officials and scholars hailed the agreement with Cuba as historic cooperation between the two countries. "I think Hemingway can be the bridge to help move both sides to a point where we can have a good, solid relationship," said McGovern, an advocate of normalizing relations between the United States and Cuba. Hemingway lived there for 21 years, more than any other place during his life. The congressman also credited the Cubans working at Finca Vigia for scanning and digitizing all the materials and working to preserve the originals and the house in Cuba, which was also part of the agreement. The JFK Library already has an extensive collection of Hemingway material — 100,000 pages of writings, 10,000 photographs, paintings and personal objects such as Hemingway's passports, flasks and wallet — thanks to a connection between Hemingway's fourth wife, Mary Welsh Hemingway, and the Kennedys. Hemingway's wife returned to Cuba in 1961 after Hemingway's death that July, hoping to retrieve his belongings from his house at Finca Vigia. Because Fidel Castro had risen to power, she asked a friend who knew the Kennedys if President Kennedy could help her get to Cuba and take Hemingway's possessions back to the United States, since the Cuban government planned to turn the estate into a Hemingway museum. The president took care of logistics within days. When Mary Hemingway decided to donate the collection to a library, Jacqueline Kennedy told her through a letter exchange that Hemingway's writings would always have a special place in the JFK Library. The collection has been available for viewing by appointment on the fifth floor since 1972 and the library boasts the most comprehensive body of Hemingway material in one place. Still, Sandra Spanier, professor of English and general editor of the Hemingway Letters Project at Pennsylvania State University, said that Mary Hemingway couldn't physically carry everything out of Cuba because of the large volume of works. Spanier was part of the group that saw what was left behind at the Hemingway Museum at Finca de Vigia in 2002, along with Jenny Phillips, a psychotherapist whose grandfather, Maxwell Perkins, was Hemingway's editor. Phillips arranged the trip through McGovern when she heard there were letters in the basement from her grandfather but couldn't gain access to them. She returned with her husband Frank, Spanier and Pulitzer Prize-winning Perkins biographer A. Scott Berg to assess the collection and look into steps to preserve it. Spanier said she got goose bumps when she saw Hemingway letters to Mary before their marriage and an original typescript of the short story "In Another Country." The microfilm copies at the JFK Library provide scholars a window into the period that occupied half of Hemingway's writing life, which before left a "black hole" in Hemingway studies because the material was off-limits to biographers, Spanier said.