:Hi Roger:  
 :I'm temporarily exhausted at this point, so I'll have to take a rest before considering another big revision. It seems that the unilateral approximations are OK only in some cases, so it might be hard to avoid some special cases. I'm OK with including the terminology 'reverse voltage gain". I chose "backward" because the symbol "B" seemed a logical choice for backward where "A" is chosen for the forward gain.  
 :I was unaware of SapWin. I'll take a look.