FIGURE 1.
Types of publications included among the 57 CC BER papers in our sample. See Supplemental Material, Part D, for descriptions of publication types.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.