COMMAND NAME:	stations

TYPE:		Data selection

SYNTAX:		"stations ABC D EF"

DESCRIPTION:

Enters a list of allowed stations into the inputs.  All alphabetic
characters are accepted, in any order, lower or upper case, with or
without spaces or commas.  Duplicate characters are ignored.  Baselines
which involve stations not in this list will fail the filter tests
applied by edit inputs, read, and plot.  Typing "stations" without
arguments removes any limitations on stations.