Classmates of Stormie Jones planted an oak in her memory and voted to name the gymnasium after the 13-year-old.

Stormie, the world's first heart-liver transplant recipient, died Sunday at Children's Hospital of Pittsburgh.Doctors undertook lab tests Monday to determine what caused her sudden death, but the tests will take up to two weeks to complete.

The flag flew at half-staff Monday at Brewer Middle School, where Stormie attended class for a few weeks in the fall before being forced home by medical problems.

The student council decided to hang a portrait of the seventh-grader in the hall and hold a pep rally Tuesday.

"They decided to dedicate the school yearbook to her, to collect donations all week for her medical bills instead of sending flowers," said student council sponsor Connie Massey.

A marker will be added where the oak was planted in front of the school, Principal Homer Dear said.

"She liked to do things for other people," said Crystal Millikan, 13, Stormie's best fried. "If you felt bad, she would make your day by saying something funny to cheer you up or by giving a gift and saying, `I love you.' "

"She was always happy and outgoing," said Steven Beam, 12. "She never made fun of anybody."

Stormie was 6 when she became the first person to receive a transplanted heart and liver at the same time. She received a second liver transplant in February.

Stormie on Saturday night was flown with a sore throat and high fever to the Pittsburgh hospital, which had performed the transplants. Her condition deteriorated rapidly.

Dr. Jorge Reyes, staff physician at Children's Hospital, said preliminary autopsy results were inconclusive.