ESENOĞLU, H. H. 1990. The sunspot observations made in 1989. Istanbul University, Faculty of Science, Journal of Astronomy and Physics, Vol.55 , no.55 , 1-22.

ESENOĞLU, H. H., (1990). The sunspot observations made in 1989. Istanbul University, Faculty of Science, Journal of Astronomy and Physics, Vol.55 , no.55, 1-22.

ESENOĞLU, Hasan. "The sunspot observations made in 1989," Istanbul University, Faculty of Science, Journal of Astronomy and Physics, Vol.55 , no.55, 1-22, 1990

ESENOĞLU, Hasan H. . "The sunspot observations made in 1989." Istanbul University, Faculty of Science, Journal of Astronomy and Physics, Vol.55 , no.55, pp.1-22, 1990

ESENOĞLU, H. H. (1990) . "The sunspot observations made in 1989." Istanbul University, Faculty of Science, Journal of Astronomy and Physics, Vol.55 , no.55, pp.1-22.

@article{article, author={Hasan Hüseyin ESENOĞLU}, title={The sunspot observations made in 1989}, journal={Istanbul University, Faculty of Science, Journal of Astronomy and Physics, Vol.55}, year=1990, pages={1-22} }