Best reference for "Software is" .. a branch of math, branch of physic

[Russell McOrmond <russell@flora.ca>]

  We have a few camps for the "software is" question in this forum.  What 
I am wondering is if the members of each camp can let me know what they 
feel to be the best publicly accessable reference that explains that 
particular way of thinking.   I have read many things over the years that 
seek to 'prove' that software is a branch of math, and others that seek to 
'prove' that software is a branch of physics.

  Let me know what each group thinks is the best.

  Also, if there are other groups that have other definitions of what
software is, and whether they consider it to be a branch of some other
field, I am interested to hear from them as well.

Thanks.

---
 Russell McOrmond, Internet Consultant: <http://www.flora.ca/> 
 Governance software that controls ICT, automates government policy, or
 electronically counts votes, shouldn't be bought any more than 
 politicians should be bought.  -- http://www.flora.ca/russell/