Suparini, S., Rusdi, R. and Ristanto, R.H. 2020. Guided discovery-blended learning (GDBL) for critical thinking skill empowerment: A learning strategy in human excretory system . Biosfer: Jurnal Pendidikan Biologi. 13, 2 (Oct. 2020), 266-279. DOI:https://doi.org/10.21009/biosferjpb.v13n2.266-279.