The Black-Scholes Calculator is based on Merton's expansion of the original Black-Scholes option pricing model, so it can calculate option prices with dividend yield. You can see more details here:
Black-Scholes Calculator (Dividend Yield Included)
You can find the assumptions behind both Black and Scholes' and Merton's version of the model explained in chapter 2 and the (very little) differences in formulas explained in chapter 9 of the calculator's user guide.
Black-Scholes and Merton's Papers
Here you can see more details about the original papers by Black+Scholes and Merton that introduced the model to the world in 1973:
- The Pricing of Options and Corporate Liabilities by Black and Scholes (1973) – the original version of the model
- Theory of Rational Option Pricing by Merton (1973) – the papers that introduced several extensions of the model, including the incorporation of dividend yield
Here you can see more information about functions and features of the Black-Scholes Calculator.