Editing .plist files - are single quotes allowed as strings?

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>font-family</key>
<array>
	<string>Arial</string>
	<string>Helvetica</string>
	<string>Georgia</string>
	<string>serif</string>
	<string>sans-serif</string>
	<string>cursive</string>
	etc...

<string>Georgia, Times, 'Times New Roman', serif</string>