Gilbert, R. P. and Kukral, D. K. (1974) “A Function-Theoretic Method for &#916;<sub>3</sub> + F(x<sub>1</sub>, x<sub>2</sub>)u = 0*”, The Journal of the Indian Mathematical Society, 38(1-4), pp. 227–231. Available at: https://www.informaticsjournals.com/index.php/jims/article/view/16696 (Accessed: 3 May 2024).