https://www.worldpranichealing.com/en/spirituality/what-is-spirituality/
https://isha.sadhguru.org/yoga/yoga_articles_spirituality/what-is-spirituality/
http://www.eckharttollenow.com/article/Oprah-Winfrey-On-Spirituality-And-Eckhart-Tolle
https://www.psychologytoday.com/us/blog/spiritual-wisdom-secular-times/201103/what-is-spirituality