For a "mainstream" approach to the "tax-foundational" view of money,  
see:  
  
http://econweb.tamu.edu/dgoldberg/research/implicit1.pdf   
  
Also, historians of thought should find this book interesting:  
  
Wray, L. Randall, ed., 2004, Credit and State Theories of Money: The  
Contributions of A. Mitchell Innes, Edward Elgar.  
  
Best,   
  
Mathew Forstater