Eisernes Kreuz 2. Klasse New Reference Book
For those where money is a bigger concern, there is the older book "Das Eiserne Kreuz 1939 Zweite Klasse" by Mario Alt, it is quite inexpensive compared to most reference books.
For those new to this hobby and looking for a good way to get Iron Cross reference books without wasting money, a good combination is the above mentioned book by Mario Alt, combined with "The Iron Cross 1st Class" by Dietrich Maertz and George Stimson. Studying these two books will give the reader a solid reference work of the majority of Iron Crosses. There are some other, very expensive books out there, but some are not worth the money. I have wasted quite a bit of money on lousy reference books.
Many people complain about the insane prices of reference books, but if you go to the actual websites, such as www.Militariafachbuch.com or bdpublish.com the prices are much more reasonable.
On Ebay or Amazon many of the reference books sell for 2 or 3 times the price that the publisher sells them at.