Unfortunately, there is not much literature on Hartheim.
A first overview is to be found on wikipedia: http://en.wikipedia.org/wiki/Hartheim_Euthanasia_Centre. The article gives proper basic information; it may be worded a bit inaccurately in two places, though. Concerning the total number of victims, one could find the article difficult to follow. Correct is that there were 30,000 people killed in Hartheim. From these were around 18,000 victims killed in the "Aktion T4" and around 12,000 killed in the "Aktion 14f13". Also, the staff mentioned in the article is only a small part of the total number of persons working in the killing centre. Altogether, around 70 individuals worked there.
In addition, you may want to read the following articles:
If you want to know more, please contact us. We will be glad to give you as much information as we can.