== Question == 

 Is it okay to use letter written from the trenches as a source when writing a wikipedia article.  For example I assume that you could use published letters to verify an oppinion of soldiers during a war, but could you use it as a verifiable source for facts?  Like when published civil war letters state that they are employeeing snipers at a certain battle, would said letter be enough to site it as a fact, or do you need further proof.  Also If the letters ARE NOT published can you use them to show oppinions of soldiers during war.  For example if I have possesion of several letters from the civil war stating that soldiers from the war stated that they dont believe the "fredom of a few nigers" is worth the war, can I thereby state that not all soldiers of the north even agreed with the abolishment of slavery.  Any info or direction you can point me to might help.