Columbia subject headings:
Harvard subject headings:
Biographies.
Heroes--United States--Biography
Railroad trains--Belgium--History--21st century.
Sadler, Anthony.
Skarlatos, Alek.
Soldiers--United States--Biography
Stone, Spencer.
Terrorism--European Union countries--Prevention--History--21st century.
Princeton subject headings:
Heroes--United States--Biography.
Railroad trains--Belgium--History--21st century.
Sadler, Anthony.
Skarlatos, Alek.
Soldiers--United States--Biography.
Stone, Spencer.
Terrorism--European Union countries--Prevention--History--21st century.