...On Causality, or the binding
Chapters on Causality and The Three Characteristics of Existence from Buddhist Philosophy: A Historical Analysis by David Kalupahana (handout)
Introduction from The Wings To Awakening by Thanissaro Bhikkhu
...On Nibbana, the unbinding
The Abstract, 'Released... with unrestricted awareness.' from The Mind Like Fire Unbound by Thanissaro Bhikkhu
Early Buddhism borrowed two of its central terms from the workings of fire. Upadana, or clinging, originally referred to the fuel that kept fire burning; nibbana, the name of the goal, to a fire's going out. This is the first book to examine these terms from the perspective of how the early Buddhists themselves viewed fire – what they saw happening as a fire burned, and what happened to the fire when it went out – to show what light this perspective throws on Buddhist doctrine in general, and the practice of meditation in particular. With extensive quotations from the Pali canon, newly translated, this is also a useful sourcebook for anyone who wants to encounter Buddhist teachings in their earliest known context.
Nibbana Sutta
Ven. Sariputta explains to Ven. Udayin how even the most exquisitely refined and beautiful mental states are beset with dukkha; only Nibbana itself can truly be called "pleasant."
Nibbana and the Paradox of Happiness by Ajahn Jagaro (comments on sutta)
Nibbana an essay by Bhikkhu Bodhi
Wikipedia article on Nibbana
Good outline overview and comparison with Mahayana & Jain ideas.
Life Isn't Just Suffering by Thanissaro Bhikkhu
The following are some of the sutras referenced by Analayo in his footnotes. The note in [brackets] refer you back to Analayo by page number / footnote number.
MN 152: Indriya-bhavana Sutta – The Development of the Faculties [109/70]
What qualifies as full mastery of the senses?
MN 18: Madhupindika Sutta – The Ball of Honey [109/71]
A man looking to pick a fight asks the Buddha to explain his doctrine. The Buddha's answer mystifies not only the man, but also a number of monks. Ven. Maha Kaccana finally provides an explanation, and in the course of doing so explains what is needed to bring the psychological sources of conflict to an end.