\label{} for internal referencing, e.g. Figure and Table numbering.

\label{fig:Lname2000_Fig7b} "fig" is a user-set class.  I also use "tbl" for tables.  "Lname2000_Fig7b" is user set too, but I recommend you adopt a naming algorithm that makes labels and citations easy to remember.

\label MUST be on the line immediately following \caption to work.