edge                    Efficient Estimation of Bid-Ask Spreads from
                        Open, High, Low, and Close Prices
edge_expanding          Expanding Estimates of Bid-Ask Spreads from
                        Open, High, Low, and Close Prices
edge_rolling            Rolling Estimates of Bid-Ask Spreads from Open,
                        High, Low, and Close Prices
sim                     Simulation of Open, High, Low, and Close Prices
spread                  Estimation of Bid-Ask Spreads from Open, High,
                        Low, and Close Prices
