COMMAND NAME:	sources

TYPE:		Data selection

SYNTAX:		"sources 3C345, 3C273, OJ287"

DESCRIPTION:

Specifies a list of sources which will pass the filters in
edit inputs, read, and plot.  The source names must match
those in the data files exactly (including case), with the
exception of leading or trailing blanks.  Typing "sources"
with no arguments removes any restriction on sources.