Sources for authentic recipes Are there any sources for authentic versions of traditional dishes? For instance I believe that the version of Guacamole that I prepare is not traditional because of the use of coriander and lime so is there any where I can look up a tradiational version of the recipe so I can compare my version with the traditional version. 

I know that even traditional recipes will vary somewhat with regional and family variations but I would have thought that there are enough elements of commonality that I could tell how my version differs.
Authentic is a very slippery question. Recipes change over time, and even the most down-home recipes are prepared differently from village to village and even house to house. As far as I know, cilantro and lime are very typical ingredients in guacamole - they are certainly included in both the Diana Kennedy and Rick Bayless standard versions, and those authors are known for their meticulous research in Mexico.