refDROP_VALUES_1 and refDROP_VALUES_2 are referenced first as owner
(schema) names, specifically the owner names of the two tables called
Drop_Value.

Those same names (refDROP_VALUES_1 and refDROP_VALUES_2) are then used
as aliases for another table owned by dbo (dbo.refDROP_VALUES). This is
very confusing naming but is perfectly legal if all the tables exist.
To demonstrate, try:

SELECT TOP 10 * FROM refDROP_VALUES_1.Drop_Value
SELECT TOP 10 * FROM refDROP_VALUES_2.Drop_Value
SELECT TOP 10 * FROM dbo.refDROP_VALUES

Lookup Owner Names in Books Online if you haven't come across two-part
names before.

--
David Portas
SQL Server MVP
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