@book{cochran_jennings_youngberg_1984, 
  title={Biomass estimators for thinned second-growth ponderosa pine trees.}, 
  DOI={10.2737/pnw-rn-415}, 
  institution={U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station}, 
  author={Cochran and Jennings and Youngberg}, 
  year={1984}
  }