On the Heavenly Spheres – Lehrbuch der Traditionellen Astrologie

https://www.amazon.de/Heavenly-Spheres-Helena-Avelar/dp/0866906096/ref=sr_1_3?crid=NF96KETFQ0NM&keywords=helena+avelar&qid=1672581732&sprefix=%2Caps%2C68&sr=8-3

https://www.academia.edu/9841145/On_the_Heavenly_Spheres

Dr. Luis Ribeiro – Historical research Astrological Techniques

–https://astrotalk.vonabisw.de/dr-luis-ribeiro-historical-research-astrological-techniques