1 1557-900x_a2018v32n6 1 1557-900x_a2021v35n9 1 1557-9646_a2019m8v66n8 1 1557-9646_a2020m1v67n1 1 1557-9646_a2020v67n5 - 1557-9654_a2021 1 1557-9654_a2021v67n11 1 15570584 1 15570584_a2018v42n4 1 1557086x 1 1557086x_a2020m1v15n1