Ismoilov , H. E. o‘g‘li, D. R. o‘g‘li Narzillayev, and K. S. qizi O‘rinboyeva. “NGC 4889: SIRLI GALAKTIKA GIGANTLARIGA QARASH”. Educational Research in Universal Sciences, vol. 2, no. 15 SPECIAL, Nov. 2023, pp. 458-61, http://erus.uz/index.php/er/article/view/4760.