References – AN 8.81: Mindfulness and Situational Awareness 
Readings by Ajahn Pasanno: [Right Mindfulness]
Right Mindfulness pp. 112-113.
Sutta: MN 44, Cūḷavedalla Sutta, The Shorter Series of Questions and Answers.
Sutta: AN 8.63: “In Brief.”
Sutta: MN 101: Devadaha Sutta, At Devadaha.
Sutta: AN 8.81: “Training.”