Do not use Google. Use Google Scholar or JSTOR. Search "Dian Xue" or "Dim Mak acupoint striking." Many PhD theses on martial arts history contain appendices with translated point charts. These are safe PDFs.
This is the most famous English-language resource. Yang, a revered master of White Crane and TCM doctor, demystified the art. His book is a textbook at martial arts colleges. A legitimate of this book is available for purchase via YMAA Publishing. Beware of pirated copies; they often omit the anatomical diagrams. dian xue shu pdf