RSI stands for Rancho San Ignacio, the breeding program of Richard Pritzlaff. If you use the search engine on this website and plug in "Pritzlaff", "Rashad Ibn Nazeer", "Bint Moniet El Nefous", "Bint El Bataa", "Rabanna", "Bint Dahma", "Yashmak", "Rasmoniet".
Also, check both the "international" and "background" sections of this website, there is a series of articles on the Nazeer sons in America. One of the articles is about Rashad Ibn Nazeer.
Finally, using Google, search for Richard Pritzlaff, which hopefully will get you to the archives of a publication called Arabian Visions. Within the archives are some really great articles about Richard Pritzlaff and Rancho San Ignacio.