vsk_cdf                 Calculating the cumulative distribution
                        function of Vasicek
vsk_imm                 Estimating Vasicek parameters by using indirect
                        moment matching
vsk_mle                 Estimating Vasicek parameters by using maximum
                        likelihood estimator
vsk_pdf                 Calculating the probability density function of
                        Vasicek
vsk_ppf                 Calculating the percentile point function of
                        Vasicek
vsk_rvs                 Generating random numbers for the Vasicek
                        distribution
