[R] good source for explaining input and output parameters of R functions

[Yan Yu]

Hello,
   thank you all for answering my previous Qs.. I have a new Q:
   I am wondering is there good source for explaning input and output
parameters of R function?
  In that aspect, I found the help documents in R is not that helpful:)
I am struggling with trying to understand what some of the returned value
means..
for example, for surf.ls() function, the help in R only describes 3
fields(the wierd thing is that those explained 3 fields are identical to
the input) of returned value, and leave a bunch of others(e.g., like "f"
and "wz"which looks pretty interesting, but i had no clue what they are
about..) unexplained.

Is there any good source if I want to understand the input and output of ,
or how to use a particular R function?

Many thanks,
yan