Bai Lin's Lip Flexibilities for All Brass Instruments
This Professor of Trumpet at the Central Conservatory in Beijing, China has composed an extraordinarily well organized 40-page book of flexibility studies which spans the elementary to advanced levels. A new standard text for brass embouchure flexibility which deservedly joins the pantheon of other such studies by Schlossberg, Irons, Colin, Smith, etc.
This book is kind of like a variation on Charles Colin's Advanced Lip Flexibilities book