What was it like in the Concentration Camp at Dachau? by Dr Johannes Neuhausler.
 
If the miracle should happen that you live to tell the tale, write it down, and tell the world what they did to us. That was the most sacred will of the comrades who died in our arms, or were removed by the invalids transport to be gassed. That was the will of brothers and true friends of the Number Men, the men who seemed to have no names but only numbers, whose ashes escaped through the chimney, and covered the fields of a foreign country.