Resources on Still Waters in general
Here you can find articles on the overall concept of Still Waters and the aspects that should be common, regardless of which service you are interested in.
Above and Below the Line
“Everything can be taken from a man but one thing: the last of the human freedoms; to choose one's attitude in any given set of circumstances, to choose one's own way.” Viktor Frankl. This quote by Viktor Frankl is the heart and soul of the simplest Challenger tool (link) I was taught; above and below the line.