Error in read_bibliography

[izzyreal18]

Hi Martin Westgate, how are you?
I have a problem with revtools. I'm trying to load my data from my systematic review with the function read_bibliography(). I'm using the bib and ris formats, but this error appears.

Error in gsub("<[[:alnum:]]{2}>", "", z) : input string 27 is invalid

I don't know what I can do to solve this problem.

Sorry for the inconvenience, but I have days trying to solve this problem.

Thanks for your attention!