Downloadable reference material available online.

https://paulrobertburton.com/imitation-of-christ-thomas-a-kempis/

https://paulrobertburton.com/the-mind-its-control-swami-budhananda/

https://paulrobertburton.com/meditation-on-om-swami-sivananda/

https://paulrobertburton.com/bhagavad-gita/

https://paulrobertburton.com/raja-yoga-swami-vivekananda/

https://paulrobertburton.com/vigils/