One of my papers was accepted by the conference. I now want to write an extended version of the paper for submission to the journal.
The journal requirements are:
Extended versions of published conference papers are welcome, but they must have at least 40% new impacting technical/scientific material in the submitted journal version, and there should be less than 30% verbatim similarity as reported by a tool (such as CrossRef). Additionally, the conference papers and the detailed summary of differences must be included as part of the journal submission to TC.
Why can't I find the tool CrossRef? I want to use some other websites to check the duplication, but how can I check the duplication only compared to my conference papers?
Has anyone experienced something like this? what should I do?