> And anyone have a reputable reference to provide   
   > a mathematical standard?   
      
   Sussman, author of SICP, wrote another 2 books:   
     Structure and Interpretation of Classical Mechanics   
     Functional Differential Geometry   
   with software scmutils.  In scmutils, you can write:   
      
   (define f (literal-function 'f (-> (UP Real Real) Real)))   
   (define g (literal-function 'g))   
   (define h (literal-function 'h))   
      
   (define Y (compose f (up g (compose h square))))   
   ((D Y) 't)   
      
   gives:   
   (+ (* 2 t ((D h) (expt t 2)) (((partial 1) f) (up (g t) (h (expt t 2)))))   
      (* ((D g) t) (((partial 0) f) (up (g t) (h (expt t 2))))))   
      
   or:   
                  / [g(t) ] \              / [g(t) ] \   
           2     |  [     ]  |            |  [     ]  |   
   2 t Dh(t ) D f|  [   2 ]  | + Dg(t) D f|  [   2 ]  |   
               1  \ [h(t )] /           0  \ [h(t )] /   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)