Query not visible for Catagory & Year

I am new to wordpress but I use to hack lots of modules in my website. I would love to thanks for this plugin to show post. I was using for News & Events of my post.

* [archivist query=”year=2012″] -> Its works
* [archivist query=”year=2013&category=Events”] -> not working

“Events” is my catagory, is the code is wrong or I need to write something else. As I have already read all the support post but din’t work for me.

Please suggest me.

http://wordpress.org/extend/plugins/archivist-custom-archive-templates/