This free chapter from Jonathan Gagne's book on the Physics of Espresso discusses the main types of espresso extraction recipes:
He also discusses filter brewing on an espresso machine, and the Nomacano/Noruego approaches.
Download PDF: free Gagne book chapter on espresso beverage recipes
This PDF was graciously provided by Scott Rao, who is the publisher of this book. You can buy The Physics of Espresso book at Scott Rao's web store. Scott has warehouses in both the USA and Germany, so it'll get to Americans and Europeans quickly and unmolested by tariff problems!
Related: Free book extract from The Physics of Espresso: Shower screens and headspace