3. I suggest liberal use of REFERENCE clause 
   for objects that represent fields exactly as defined 
   in an underlying protocol specification. 
   For example ipv6DefaultHopLimit
   as specified in 2460 sec 3, 8.2). For a well
   developed example, see RFC 2674.
   http://www.nanog.org/mtg-0102/ppt/mibs/sld010.htm