“…There have been many different RRTs developed since Warner's original method, such as in Greenberg et al [36,37], Gupta [38], Gupta et al [39][40][41], Yu et al [42], Sihm et al [43], Gupta and Shabbir [44], and so on. Efforts specifically have been made to improve the efficiency of the technique by reducing the variance and thus the confidence intervals, because, the primary disadvantage of the Warner's model, and in fact of all RRTs, is that the variances of the estimators are higher than the ones that could be obtained from DQ [35,45]; for a comprehensive review of RRTs, interested readers are referred to Chaudhuri and Mukerjee [35], Chaudhuri [46], and Chaudhuri and Christofides [47]. In the next subsection, we will review some real-life applications of RRTs and their comparisons with other surveying techniques.…”