Following the procedures established by the creators of the BNC, the PERC Corpus project team sent letters to major journal publishers asking for permission to use copyrighted material. Requests were sent to more than 1,500 journals. At present, copyright clearance has been obtained for nearly 300 journals from over 60 publishers.
The End User license strictly regulates the use of the PERC Corpus and the text samples it contains. The right of reproduction of individual original text samples by any means is explicitly prohibited. No text samples in their original form can be incorporated into any product. Quotations from text samples are strictly limited to the fair use provisions of copyright law.