This list will be updated as other sources are mentioned.
Studies and exercises:
Stutschewsky:
https://en.schott-music.com/shop/violoncello-technik-no32085.html
Rick Mooney:
Double Stops for Cello
https://blackwells.co.uk/bookshop/product/Double-Stops-for-Cello-by-Rick-Mooney-author/9780874877618
Position Pieces for Cello, Books 1 and 2:
https://blackwells.co.uk/bookshop/product/Position-Pieces-for-Cello-by-Rick-Mooney-author/9780874877625
Thumb Position for Cello, Books 1 and 2 :
Books about technique:
Christopher Bunting:
Essay on the Craft of Cello Playing, Volumes 1 and 2
https://blackwells.co.uk/bookshop/product/Essay-on-the-Craft-of-Cello-Playing-Vol-1-Prelude-Bowing-Coordination-by-Christopher-Bunting/9780952790228
Gerhard Mantel: Practising Etudes:
https://blackwells.co.uk/bookshop/product/Practising-Etudes-by-Gerhard-Mantel/9783795745745
Other interesting material of performance
Timothy Galway: The Inner Game of Tennis
https://blackwells.co.uk/bookshop/product/The-Inner-Game-of-Tennis-by-W-Timothy-Gallwey-author/9781447288503
Online articles:
https://bulletproofmusician.com/how-many-hours-a-day-should-you-practice/
https://bulletproofmusician.com/what-every-musician-ought-to-know-about-stage-fright/
Websites:
http://www.celloprofessor.com/
http://www.emilyplayscello.com/video/
http://www.saundersrecorders.com/
http://www.cello.org/Newsletter/Articles/mantel.htm
Music blogs that I follow: