AmeriGas Partners, L.P.

Dorchester Minerals, L.P.

Enbridge Energy Partners, L.P.

Enterprise Products Partners L.P.

Exterran Partners, L.P.

Ferrellgas Partners, L.P.

Kinder Morgan Energy Partners, L.P.

Legacy Reserves LP

Linn Energy, LLC

Magellan Midstream Partners, L.P.

Natural Resource Partners L.P.

NuStar Energy, L.P.

ONEOK Partners, L.P.

Plains All American Pipeline, L.P.

Rose Rock Midstream, L.P.

Sunoco Logistics Partners, L.P.

TC PipeLines, LP

Tesoro Logistics LP

Vanguard Natural Resources, LLC