F. A. Noor, M. Abdullah, S. Sukirno, and K. Khairurrijal, “Comparison of Electron Direct Tunneling Time in a Heterostructure with a Nanometer-Thick Trapezoidal Barrier Calculated Using Exponential and Airy Wavefunctions”, ijp, vol. 18, no. 1, pp. 1-4, Nov. 2016.