SQL Server 2008 :: Queries To Simulate INTERSECT And EXCEPT But With Records In Same Table

Here's the scenario. I have a table (let's call it MyTable) that consists of four fields: Id, Source, FirstField, and SecondField, where Source only takes one of two values: Source1 and Source2.

The records in this table look as follows:

I need to return, using 3 different T-SQL queries:

1) Products that exist only in Source2 (in red above)

2) Products that exist only in Source1 (in green above)

3) Products that exist both in Source1 and Source2 (in black above)

For 1) so far I've been doing something along the lines of

SELECT * FROM MyTable WHERE Source=Source1 AND FirstField NOT IN (SELECT DISTINCT(FirstField) FROM MyTable WHERE Source=Source2)

Not being a T-SQL expert myself, I'm wondering if this is the right or more efficient way to go. I have read about INTERSECT and EXCEPT, but I am a little unclear if they could be applied in this case out of the box.