Guerrero Ortiz, Carolina, et al. “Difficulties Experienced by Students in the Interpretation of the Solutions of Ordinary Differential Equations That Models a Problem”. Enseñanza De Las Ciencias. Revista De investigación Y Experiencias didácticas, vol. 28, no. 3, Apr. 2011, pp. 341-52, doi:10.5565/rev/ec/v28n3.431.