An introduction to basic principles of object oriented programming
Further links that may be of use: S4 classes https://www.r-project.org/conferences/useR-2004/Keynotes/Leisch.pdfObject oriented programming S3 classes http://adv-r.had.co.nz/S3.html Online slides on OOP in R http://logic.sysbiol.cam.ac.uk/teaching/advancedR/slides.pdf