A Note on the Quartic Diophantine Equation $A^4+h{B}^4=C^4+h{D}^4$

Integer solutions of the diophantine equation $A^4+h{B}^4=C^4+h{D}^4$ are known for all positive integer values of $h<1000$. While a solution of the aforementioned diophantine equation for any arbitrary positive integer value of $h$ is not known, Gerardin and Piezas found solutions of this equation when $h$ is given by polynomials of degrees 5 and 2 respectively. In this paper, we present several new solutions of this equation when $h$ is given by polynomials of degrees $2,3$ and 4.