I was disappointed they didnít discuss momentum. They alluded to it under the discussion "AFFECT OF ARROW MASS ON ARROW VELOCITY"
I found it to be great read though, for all archery hunters; not just the crossbow users.
Basically the main point of the article is that crossbows have comparable energy as today's compounds. They won't kill a deer any quicker than a compound. It goes into several calculations and explanations as to why this is true.