Multiple URL with comma not working

First of all, congrats and many thanks for giving us such a wonderful tool.

I am struggling a little bit regarding multiple URLs. I read the thread “Multiple URLs” where example for including multiple URLs was given. I gave a try but the feed from only one URL is getting retrieved.

[wp_rss_retriever url=”http://feeds.nature.com/nature/rss/current, http://rss.sciencedirect.com/publication/science/00928674″ items=”10″ excerpt=”50″ read_more=”true” credits=”true” new_window=”true” thumbnail=”200″ cache=”12 hours”]

However, when I tried the other way around [see the code below] it is working perfectly.

[wp_rss_retriever url=”http://rss.sciencedirect.com/publication/science/00928674″ items=”10″ excerpt=”50″ read_more=”true” credits=”true” new_window=”true” thumbnail=”200″ cache=”12 hours”]

[wp_rss_retriever url=”http://feeds.nature.com/nature/rss/current” items=”10″ excerpt=”50″ read_more=”true” credits=”true” new_window=”true” thumbnail=”200″ cache=”12 hours”]

Can you please help?

Also, I like to list the feeds retrieved from multiple URLs alphabetically. Is it possible?

Thanks.