WASET
    Ahmed H. Abdullah and  Pavel Kroupa,  Specific Frequency of Globular Clusters in Different Galaxy Types.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    August 2018, vol. 141(9). 190 - 195
    [viewed 28 April 2024]. Available from: https://publications.waset.org/pdf/10009520.