# How do you calculate cohen's L so that you can plug it into a power calculation for multiple linear regression?

I am reviewing a book called Statistical Methods for Healthcare Research so I can learn how to do a power calculation for my sample size for multiple linear regression.

This book says that cohen provides the following formula: $$N = L(1-R^2)/R^2 + u + 1$$. It says that $$L$$ can be obtained from a table and it is defined by Cohen as a function of power and number of independent variables at a given $$\alpha$$-level.

I have looked in Cohen's 1988 book (the only one I have access to) and cannot find how to do this.

Does anyone know where I can obtain the value of $$L$$ for $$4$$ independent variables with a power of $$80\%$$ and an $$\alpha$$ of $$0.05$$?