References – AN 8.30: Anuruddha 
Readings by Ajahn Karuṇadhammo: [Proliferation] [Perception]
Sutta: MN 18: Madhupiṇḍika Sutta, The Honeyball.
“Categorical Answers,” Skill in Questions by Ajahn Ṭhānissaro, p. 85.
Sutta: AN 8.30: “Anuruddha.”
The Four Foundations of Mindfulness [2015], Session 48
Discussion of the meaning of papañca in AN 8.30 and various other suttas. [Pāli] [Translation] [Proliferation] [Perception] // [Great disciples] [Liberation] [Conditionality] [Directed thought and evaluation] [Language]
Suttas: Snp 4.11: Kalahavivāda Sutta and DN 21: Sakkapañha Sutta in which papañca precedes thinking.
Reference: Skill in Questions by Ajahn Ṭhānissaro, p. 85.
Suttas: MN 19: Dvedhāvitakka Sutta; MN 20: Vitakkasaṇṭhāna Sutta.
Reference: Concept and Reality in Early Buddhist Thought by Bhikkhu Ñāṇananda
The Four Foundations of Mindfulness [2015], Session 48, Excerpt 1
Readings by Ajahn Pasanno:
The Island by Ajahn Pasanno and Ajahn Amaro, Chapter 15, pp. 274-277:
Suttas: AN 8.30; SN 2.5; AN 3.83; SN 52.9; MN 123.22; MN 122.4, .6 & .7.
Sutta: MN 123: Wonderful and Marvelous.