Herr Marcus Schmidt ,
I have the one book by Porth, which is misplaced and Meyer pages missing [they fell out]. Once I find it, I don't mind helping for Himbergen Uelzen. Unless someone has already helped. Feel free to email me at address or even arootdigger (at) gmail.com. I do have s string of Schulz in that book that may be with mind. I must admit the translation I did with google translation did not give me a full realization of most what you wrote. No offense please. I will try another also.
Jo Meyer