@online{olson,
  author = {Olson, Dieter},
  title = {Theory {Series,} {Part} 4: {Worked} {Pendulum} {Dynamics}},
  date = {},
  url = {https://affinedrift.com/articles/theory-part4.html},
  langid = {en},
  abstract = {This article develops explicit analytical derivations and
    reproducible numerical examples for loaded beam and multi-link
    pendulum models of the golf swing. It explores how shaft
    flexibility, boundary conditions, and actuator torques interact to
    produce non-collinear acceleration components.}
}