Torben Ægidius Mogensen's "Basics of Compiler Design, Chapter 5: Interpretation"
Read Chapter 5 on interpretation, where execution of a program takes place as the derivation is produced.
Click http://web.archive.org/web/20120915222417/http://www.diku.dk/hjemmesider/ansatte/torbenm/Basics/basics_lulu2.pdf link to open resource.