2.3.1.1. Video: F vs V | English Pronunciation Lesson - YouTube - https://www.youtube.com/watch?v=3f4kN4kX4U

2.3.1.2. Video: Minimal Pairs: /f/ vs /v/ - YouTube - https://www.youtube.com/watch?v=9kX4kC1L9X0I

2.3.1.3. Article: Minimal Pair /f/ and /v/ | Learn English - https://www.englishclub.com/pronunciation/minimal-pairs-f-v.php

2.3.1.4. Article: English Pronunciation: /f/ vs /v/ - Pronunciation Studio - https://pronunciationstudio.com/f-v/