Ana Paula Esteves and  Diego S. Caetano and  Louise L. B. Lomardo,  The Importance of Zenithal Lighting Systems for Natural Light Gains and for Local Energy Generation in Brazil.   journal   = {International Journal of Urban and Civil Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2018, vol. 138(6). 682 - 687
    [viewed 26 April 2024]. Available from: https://publications.waset.org/pdf/10009210.