Peter Harvey (2015). Steven M. Emmanuel (บ.ก.). A Companion to Buddhist Philosophy. John Wiley & Sons. pp. 26–44. ISBN978-1-119-14466-3. Quote: "the first features described as painful [dukkha] in the above DCPS [Dhamma-cakka-pavatana Sutta in Vinaya Pitaka] quote are basic biological aspects of being alive, each of which can be traumatic. The dukkha of these is compounded by the rebirth perspective of Buddhism, for this involves repeated re-birth, re-aging, re-sickness, and re-death."