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/