Once you are familiar with the basic notes and articles on spinning here is some more advanced information:

Spinning the Pitts and Eagle

• Spins in the Christen Eagle II
  

General Articles on Advanced Spinning

• Unrecoverable Spins
  
• Goulian Advanced Spinning
• Hammer Spins Revisited
• Inverted Spins by Bill Finagin
• Yak 52 Spinning
• The Spin That Shocked by Dave Monds
• The Spin by Brian Lecomber
  • The Spin Continued

Beggs-Mueller

• Mueller Spin Recovery
• Out Spinning With Beggs Part 1
• Out Spinning With Beggs Part 2
• SpinOffs Beggs Part 1
• SpinOffs Beggs Part 2
• SpinOffs Beggs Part 3
• Spinning With Gene Beggs – The End