Columbia subject headings:
Diffusion of innovations--Congresses.
Law enforcement--United States--Congresses.
Police--United States--Congresses.
Harvard subject headings:
Diffusion of innovations--Congresses.
Law enforcement--United States--Congresses.
Police--United States--Congresses.
Princeton subject headings:
Diffusion of innovations--Congresses.
Law enforcement--United States--Congresses.
Police--United States--Congresses.