The body of celebrated auto designer and race car driver Carroll Shelby, who died more than a month ago, could remain in a Dallas morgue for several more weeks while his family fights about burial plans, his sons said Tuesday.

Shelby's three children say their father, who died May 10 in a Dallas hospital, signed a document in February giving them permission to have his body cremated. His wife, Cleo Shelby, who lives in California, alleges the signature on that directive is a forgery. She says a document signed two years ago gives her power of attorney in Shelby's affairs.

Shelby's son Michael Shelby told The Associated Press on Tuesday that several witnesses watched his father sign the paperwork in February and ''there was absolutely no way'' Cleo Shelby could substantiate her claims.

''It's not children's wishes versus the wife,'' Michael Shelby said. ''It's his written wishes versus Cleo Shelby.''

Both sides have filed documents in a lawsuit pending in Dallas County court. In the meantime, Shelby's body remains in the custody of the Dallas medical examiner's office, which did not immediately return messages seeking comment.

''There's just a lack of closure in a situation where he did have a nice, long life,'' said another of Carroll Shelby's sons, Patrick. ''He's got relatives down in East Texas, and we're just not able to get this chapter closed. And I'm not really sure what the reasoning is.''

Shelby was a champion race car driver who built powerful engines for Ford's Mustang and Chrysler's Viper. His iconic last name is stamped onto dozens of sports car models, including a new Mustang Shelby GT500 that he tested months before his death.

When he died at age 89, Shelby also was one of the nation's longest-living heart transplant recipients and later started the Carroll Shelby Foundation for children and young people needing acute coronary and kidney care.