chapter  9
Hydraulic Flow, Pressure Drop, and Response
Pages 51

There's no lack of information on pressure losses in piping, fittings, and restrictions. Pioneers such as Bernoulli, Poiseuille, Darcy, Weisbach, Moody, Pigott, Reynolds, and Petroff set down the rules for flow. Those relationships-at least the ones of most interest to designers of fluid power piping and systems-haven't changed much.