İnci M. Erhan,  An Expansion Method for Schrödinger Equation of Quantum Billiards with Arbitrary Shapes.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    May 2007, vol. 5(5). 255 - 258
    [viewed 28 May 2022]. Available from: https://publications.waset.org/pdf/1846.