@article{soest1991,
  title={Methods for Dietary Fiber, Neutral Detergent Fiber, and Nonstarch Polysaccharides in Relation to Animal Nutrition},
  author={P.J. Van Soest and James B. Robertson and B.A. Lewis},
  year={1991},
  journal={Journal of Dairy Science},
  doi={10.3168/jds.s0022-0302(91)78551-2},
  url={https://doi.org/10.3168/jds.s0022-0302(91)78551-2}
}