Literary feud sparked by a Graham Greene comma

At the end of the affair, a bitter literary argument involving one Britain's most revered writers may come down to the matter of a single comma.

Two days before his death in April 1991, Graham Greene signed a one-sentence note that made it clear he had authorised one person – Norman Sherry – to complete an authorised biography.

But before he signed the note, Greene inserted the comma that is at the centre of an increasingly acerbic row between the writer's estate, Professor Sherry and a host of other writers who claim they are being denied access to documents essential for their work.

A large cache of Greene's writings are held by the Lauinger Library at Georgetown University in Washington. Greene's family, which controls his estate, has given permission to several writers to quote from the archive to complete their own works, including a biography of Edith Sitwell, who engaged in lengthy correspondence with Greene. But the library claims Greene made it clear that Professor Sherry should have first access.

Artemis Kirk, the university librarian, told The New York Times: "We take our role as stewards of collections and gifts very seriously and therefore are careful to balance open access with the responsibilities incumbent upon us."

News of the row emerged several weeks ago, but since then a growing number of writers have come forward to claim their own projects are being stalled. Firdaus Gandavia, a Greene scholar from Calcutta, is now years behind on a project for the St Martin's Press.

"What am I supposed to tell [them]," he asked, citing a number of e-mail messages from Professor Sherry, expressing his desire that he does not want anyone else having "unlimited access".

Richard Greene, a professor of English at Toronto University who is unrelated to the writer and is working on a biography of the poet Edith Sitwell, said he had been forced to proceed without having read crucial letters between the two writers.

"It's a major gap and a really important episode in her life is going to remain more or less unexplained because of this absence," he said. "My concern is that [Professor Sherry's] taking an enormous amount of time should not prevent other work being done by other people."

Greene's family want the "stranglehold lifted". His son and literary executor, Francis Greene, said: "Graham gave his papers for the good of the scholarship of the readers of the world and they have been withheld from everybody."

The estate even questions the meaning of Greene's final statement, which says: "I Graham Greene grant permission to Norman Sherry, my authorised biographer, excluding any other to quote from my copyright material published or unpublished." Before he signed the document, Greene inserted a comma between the words "other" and "to", apparently shifting the meaning to suggest that while Mr Sherry was the sole authorised biographer, the matter of whether other writers could quote from the papers was left open.

Professor Sherry, who Greene appointed his biographer on the strength of two unauthorised volumes, has been largely silent on the matter, saying he is too busy completing the two further commissioned volumes, that have still not appeared 11 years after Greene's death. Yesterday, Professor Sherry, based at Trinity University in San Antonio, Texas, was again unavailable.