Today, I know that books can be searched by the Google book search. I had found the books who refer to PU2RC. The reference statements in each book are displayed with the page number. Moreover, I added reference statements for each reference materials. Since the Google scholar search seems not to show the number of citations for not paper documentation such as standard contributions.
I wish to upgrade PU2RC documents to sent to a request. I will give him the citation list of PU2RC together with evidence notes. Each citation statement includes evidence information such as the text referring to any PU2RC source document. For example, if paper A refer to PU2RC paper X, I will describe the sentence which refers to PU2RC paper X below the statement of the index of paper A. The addition of evidence information will improve the reliability of my documentation of PU2RC status.