https://www.youtube.com/c/TheAstraProject/videos
Ibn Ezra – http://opac.tib.eu/DB=3/SET=5/TTL=11/FAM?PPN=1391676246
Abū-Maʿšar Ǧaʿfar Ibn-Muḥammad – http://opac.tib.eu/DB=3/SET=9/TTL=1/FAM?PPN=166372993X
Wilhelm Gundel – http://opac.tib.eu/DB=3/SET=11/TTL=2/MAT=/NOMAT=T/CLK?IKT=1004&TRM=Gundel,Wilhelm