Bireswar Paul and  Amitava Datta,  Existence of Nano-Organic Carbon Particles below the Size Range of 10 nm in the Indoor Air Environment.   journal   = {International Journal of Energy and Power Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2017, vol. 127(7). 1326 - 1331
    [viewed 15 October 2019]. Available from: https://publications.waset.org/pdf/10007486.