information about Loess

Hello,

I'm currently using a tool that provides a Loess fitting, but I obtained results that are slightly different from those provided by R implementation of the Loess. That's why I would like to know if you could give me a source (bibliography or web) that explains in a clear way each step of the algorithm, with the possible options to choose, etc.. in order for me to understand those differences.

Thank you,

Naomi Berdugo.