References – SN 12.15: Kaccanagotta 
“Is there a way to stabilize the perception of impermanence?” Answered by Ajahn Pasanno and Ajahn Jotipālo. [Perception] [Impermanence] // [Cessation] [Relinquishment] [Suffering]
Sutta: SN 12.15: Kaccānagotta.
Western Disciples of the Thai Forest Tradition [2016], Session 56, Excerpt 3
Readings from The Island by Ajahn Pasanno and Ajahn Amaro, Chapter 5, pp. 105-109. Read by Ajahn Amaro:
Suttas: MN 75.12; MN 74.2-5; MN 102.12; Iti 49; SN 12.15, SN 22.90.
Vinaya: Mahāvagga 1.6 (also at SN 22.59).
Readings from The Island [2025], Session 19
Readings from The Island by Ajahn Pasanno and Ajahn Amaro, Chapter 13, pp. 239-246. Read by Ajahn Pasanno:
Suttas: Snp 1106-7 & 1111; Snp 1098; AN 1.182; SN 12.15; Iti 49; SN 12.48; SN 12.18; SN 12.67.
Readings from The Island [2025], Session 28
“Is [SN 12.15] specifically what the middle way refers to?” Answered by Ajahn Amaro. [Middle Path] // [Dependent origination] [Eightfold Path] [Sense bases] [Philosophy]
Sutta: SN 56.11: Dhammacakkappavattana Sutta (Chanting book translation).
Reference: Concept and Reality by Bhikkhu Ñāṇananda p. 63, quoted in The Island by Ajahn Pasanno and Ajahn Amaro, p. 140.
Sutta: SN 2.26: Rohitassa.
Sutta: DN 11.85: Where earth, water, fire, and air no footing find...