Irving Stone

Greeting Card Executive

Irving Stone, 90, who started working in his family's greeting card business at age 5 and helped transform it into American Greetings Corp., one of the world's largest card makers, died Jan. 17, the Associated Press reported in Cleveland. No cause of death was announced.

Mr. Stone's father, Jacob Sapirstein, founded American Greetings Corp. in 1906 by selling picture postcards from his wagon. By age 9, Mr. Stone had become a partner in the company and handled every aspect of the business, from sales to delivery to billing, for two months while his father was ill. He was the company's bookkeeper by age 12.

Dissatisfied with the quality of cards the family was buying for resale, Mr. Stone got the company to begin designing and printing its own cards in the 1930s. One of his earliest verses, "From Someone Who Likes To Remember Someone Too Nice To Forget," has sold more cards than any other in the company's history and is still part of the line. Mr. Stone became company president in 1960 and was promoted to chairman of the board and chief executive officer in 1978.

Robert Rathbun Wilson

Nuclear Physicist

Robert Rathbun Wilson, 85, an influential nuclear physicist who was a leader in the Manhattan Project, died Jan. 16 at his home in Ithaca, N.Y., of complications from a stroke suffered a year ago.

In 1942, he collaborated with Enrico Fermi at the Massachusetts Institute of Technology on experiments that led to the atomic bomb. Mr. Wilson's job was designing particle accelerators. The work at MIT was a precursor to the secretive World War II effort known as the Manhattan Project. Mr. Wilson invented an electromechanical method for separating uranium isotopes that became known as the Isotron method.

In 1943, Mr. Wilson and colleagues moved their work to Los Alamos, N.M. There he headed the Experimental Nuclear Physics Division.

He also served as director of the National Accelerator Laboratory in Batavia, Ill., which, at four miles long, was one of the world's largest physics facilities.

Clifford A. Truesdell III

Mathematician and Author

Clifford A. Truesdell III, 80, an award-winning mathematician, author and professor of rational mechanics at Johns Hopkins University from 1961 to 1989, died of congestive heart failure Jan. 14 at a Baltimore nursing home.

Dr. Truesdell graduated from the California Institute of Technology with bachelor's degrees in physics and mathematics and a master's degree in mathematics. He received a mathematics doctorate from Princeton University.

In the Washington area from the mid-1940s, he headed the theoretical mechanics subdivision of the Naval Ordnance Lab and the theoretical mechanics section of the Naval Research Laboratory.

He wrote 26 books since, including "Rational Thermodynamics" and "An Idiot's Fugitive Essays on Science: Methods, Criticism, Training, Circumstances," and he helped start and edit several journals, including the Archive for Rational Mechanics and the Archive for History of Exact Sciences.

His honors include the Bingham Medal of the Society of Rheology in 1963 and the Birkhoff Prize of the American Mathematical Society in 1978.