Fernbach S K, Tucker G F
Radiology. 1986 Feb;158(2):512. doi: 10.1148/radiology.158.2.3941880.
The United States of America changed the composition of the penny in 1982. It is now a copper-plated, zinc-based coin. Erosions of the edge of this new coin were observed when it was impacted in the esophagus of a 13-month-old child.