He told her that his work in the emergency room of an American hospital had given him expert knowledge of the most effective ways to kill oneself.
Times, Sunday Times (2010)
The dichotomous key was formulated on "expert knowledge" and validated against field estimates of body composition.
Gary Kofinas, Phil Lyver, Don Russell, Robert White, Augie Nelson, Nicholas Flanders 2003, 'Towards a protocol for community monitoring of caribou body condition', Rangifer