Aside: URLs, URIs, and URNs

• URI: Uniform Resource Identifier
  • URL: Uniform Resource Locator
  • URN: Uniform Resource Name

A book example ("Leadership in Turbulent Times" by Doris Kearns Goodwin).

• urn:isbn:9781476795928 - Uniquely identifies by "name"
• https://www.barnesandnoble.com/w/leadership-doris-kearns-goodwin/1128008541?ean=9781476795928#/ - URL, "L" is for "Locator"; tells you were something is "at"

Both are "URIs" one is a URN and the other is a URL.