M. Antony Arockiasamy, V. Saraswathi, and P. Sathya. “Cordial And Product Cordial Labeling Of Edge Merged And Vertex Merged N-Chain Aztec Diamond Graphs”. International Journal of Mathematics And Its Applications, vol. 6, no. 1 (Special Issue), May 2018, pp. 195-02, http://ijmaa.in/index.php/ijmaa/article/view/1413.