Kim Hoi, Huynh Thi, et al. “Effects of Some Physic - Chemical Characteristics of the Soil on Earthworms at the Tam Dao National Park, Vinh Phuc Province”. Academia Journal of Biology, vol. 29, no. 2, Nov. 2014, pp. 26-34, doi:10.15625/0866-7160/v29n2.5370.