At this time, I am not sure where I found his books that I am currently reading. I searched for Franz Schumi in old newspapers and found his simple obituary.

Neue Freie Presse
Oct 10 1918 • Vienna, Austria

Wie aus Zürich gemeldet wird, starb dort vor einiger Zeit Herr Franz Schumi, Schriftfieller, im Alter von 70 Jahren. Er lebte längere Zeit auch in Gicz und verfaßte mehrere Heimatfundliche Werte über Krain, unter anderm "Archiv für Heimatfunde" und "Urfunden und Registerbücher".

Translation

As reported from Zurich, some time ago, Mr. Franz Schumi, a writer, passed away at the age of 70. He also lived for a long time in Gicz and wrote several valuable works on Krain, including "Archive for Local Discoveries" and "Ancient Finds and Registry Books."

I searched for the two book titles given in the old newspaper and found them. They are in German. They would need to be translated for me to read them.

Archive for Local Discoveries, by Franz Schumi
Appears to be a German historical record

Volume 1: text

Volume 2: djvu

Ancient Finds and Registry Books of the Duchy of Carniola, by Franz Schumi
What is the Duchy of Carniola? (I asked AI)

The Duchy of Carniola, also known as the Duchy of Krain, was a historic administrative region within the Habsburg Monarchy and later the Austrian Empire. It was located in present-day Slovenia and its capital was Ljubljana. The Duchy of Carniola existed from the late Middle Ages until the early 20th century. It played a significant role in the cultural, political, and economic history of the region.

Slovenia is where the US president's third wife, Melania, was born.

This book appears to be more old German historical records: djvu

Franz Schumi books in English (.mobi files)

When I found some of his books in English, I realized I found treasure. I don't have the direct links at this time, but here are the books I have read so far, which I am sharing with anyone who would like to take a look.

21a - The Resurrection of Jesus Christ

55 - The Soul

The reincarnated House of David

2 Timothy 4:13 | The cloke that I left at Troas with Carpus, when thou comest, bring with thee, and the books, but especially the parchments.