Winckler, M. V., Marques, R., Soares, R. V., & Watzlawick, L. F. (2006). Index of efficiency of macronutrients in tree species in a mixed araucaria forest/Paraná State. Semina: Ciências Agrárias, 27(3), 321–332. https://doi.org/10.5433/1679-0359.2006v27n3p321