id	domain	url
stem-6989	openconference.us	https://openconference.us/index.php/ysc/article/view/804
stem-6989	www.in-academy.uz	https://www.in-academy.uz/index.php/ejsspc/article/view/14638
stem-6989	doi.org	https://doi.org/10.5281
stem-6989	doi.org	https://doi.org/10.4324/9780203427095-18
stem-6989	doi.org	https://doi.org/10.1007/s10943-006-9030-0
stem-6989	doi.org	https://doi.org/10.1080/00497878.2011.527783