Click on the following links. Please note these will open in a new window.

Knock and Announce Requirement
http://law.jrank.org/pages/10055/Search-Seizure-Knock-Announce-Requirement.html

13 Warrantless Searches
http://www.superheronation.com/2011/05/03/12-legal-warrantless-searches/

Searching a Cell Phone Incident to Arrest
https://www.washingtonpost.com/news/volokh-conspiracy/wp/2014/02/17/searching-a-cell-phone-incident-to-arrest-possible-fourth-amendment-rules-that-the-supreme-court-might-consider-in-riley-and-wurie/