So in short, be safe, make sure your URLs do not have spaces in them. It is best to use hyphens, but you can close the wholes with the + or "%20" but it is probably best to use hyphens.
Google's John Mueller said in a Google Webmaster Help thread that you should avoid using special characters in your URLs. Specifically avoid using "commas, semicolons, colons, spaces, quotes, etc." in ...
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