- Jim Collins o konceptu ježka
https://www.jimcollins.com/media_topics/PersonalHedgehogConcept.html, https://www.jimcollins.com/concepts/the-hedgehog-concept.html - Daniel Goleman, Emoční inteligence (knihy dostupné ve vašem jazyce)
- Model osobnosti Big Five Wikipedia
- Model osobnosti Big Five Verywell Mind