In Piper Aircraft Co. v. Reyno (1981) 454 U.S. 235, the United States Supreme Court explained the "Court of Appeals found that the problems of proof could not be given any weight because Piper and Hartzell failed to describe with specificity the evidence they would not be able to obtain if trial were held in the United States. It suggested that defendants seeking forum non conveniens dismissal must submit affidavits identifying the witnesses they would call and the testimony these witnesses would provide if the trial were held in the alternative forum. Such detail is not necessary. Piper and Hartzell have moved for dismissal precisely because many crucial witnesses are located beyond the reach of compulsory process, and thus are difficult to identify or interview. Requiring extensive investigation would defeat the purpose of their motion. Of course, defendants must provide enough information to enable the District Court to balance the parties' interests. Our examination of the record convinces us that sufficient information was provided here." (Id. at pp. 258-259, )