Is the Pearson r2 biased, and if so, what is the best correction formula?

In this study the authors investigated the use of 5 (i.e., Claudy, Ezekiel, Olkin-Pratt, Pratt, and Smith) R-2 correction formulas with the Pearson r(2). The authors estimated adjustment bias and precision under 6 x 3 x 6 conditions (i.e., population rho values of .0, .1, .3, .5, .7, and .9; population shapes normal, skewness = kurtosis = 1, and skewness = -1.5 with kurtosis = 3.5; ns = 10, 20, 40, 60, 100, and 200 respectively). Results indicate that the sample Pearson r(2) is marginally biased at small sample sizes and small population effect sizes, and that the Ezekiel and the Smith R-2 corrections work well in controlling this bias.