Beethoven power pack

https://archive.org/details/beethovenwithint00riez

>Walter Riezler - Beethoven; with an introduction by Wilhelm Furtwängler (1938)

https://archive.org/details/in.ernet.dli.2015.80581

>Donald Francis Tovey - Beethoven (1945)

http://gen.lib.rus.ec/book/index.php?md5=42C93E1FB466019048F4EC4BCCDE15A2

>Edwin Fischer - Beethoven's pianoforte sonatas: a guide for students & amateurs (1959)