@online{olson,
  author = {Olson, Dieter},
  title = {Theory {Series,} {Part} 3: {Drift} {Invariance} and {Force}
    {Taxonomy}},
  date = {},
  url = {https://affinedrift.com/articles/theory-part3.html},
  langid = {en},
  abstract = {This article establishes the mathematical meaning of drift
    invariance in multibody mechanics and constructs an exhaustive
    taxonomy of forces in the golf swing. It explores velocity-dependent
    passive reactions, muscular actuation, and constraints, setting
    boundaries where affine assumptions remain valid.}
}