Exploring the effects of following up with individuals at high risk for suicide:
https://suicidepreventionlifeline.org/wp-content/uploads/2016/09/Lifeline-Crisis-Center-ED-Paper-1.6.pdf

Protocol for assessing suicide crisis call content and quality:
https://www.rand.org/pubs/periodicals/health-quarterly/issues/v5/n3/08.html

Research and evaluation of crisis helplines (and what techniques are successful):
https://www.lifeline.org.au/static/uploads/files/summary-of-research-and-evaluation-of-crisis-helplines-january-2013-wfneenqlkynw.pdf

Crisis intervention guidelines:
https://acws.ca/sites/default/files/documents/6-CrisisIntervention.pdf