Victorbabu, B. R., and C. V. Surekha. “On Measure of Second Order Slope Rotatable Designs Using Partially Balanced Incomplete Block Type Designs”. Thailand Statistician, vol. 11, no. 2, May 2015, pp. 159-71, https://ph02.tci-thaijo.org/index.php/thaistat/article/view/34221.