AllianceBernstein Holding L.P.

American Midstream Partners, LP

AmeriGas Partners, L.P.

Atlas Pipeline Partners, L.P.

The Blackstone Group

Blueknight Energy Partners, L.P.

Boardwalk Pipeline Partners, LP*

Brookfield Infrastructure Partners L.P.

Buckeye Partners, L.P.*

Calumet Specialty Products Partners, L.P.

Central Energy Partners, L.P.*

Cheniere Energy Partners, L.P.*

Chesapeake Midstream Partners LP

Compressco Partners, L.P.

Constellation Energy Partners LLC*

Copano Energy, L.L.C.*

Crestwood Midstream Partners LP*

Crosstex Energy, L.P.*

CVR Partners, LP*

DCP Midstream Partners, L.P.

Dorchester Minerals, L.P.*

Eagle Rock Energy Partners, L.P.*

El Paso Pipeline Partners, L.P.*

Enbridge Energy Partners, L.P.*

Energy Transfer Partners, L.P.*

Enterprise Products Partners L.P.*

EV Energy Partners, L.P.*

Exterran Partners, L.P.*

Ferrellgas Partners, L.P.

Fortress Investment Group LLC

Genesis Energy, L.P.*

Holly Energy Partners, L.P.*

Inergy, L.P.

Kinder Morgan Energy Partners, L.P.*

KKR & Co. L.P.

Legacy Reserves LP.*

Linn Energy, LLC*

LRR Energy, L.P.*

Magellan Midstream Partners L.P.

MarkWest Energy Partners, L.P.

Martin Midstream Partners, L.P.*

Memorial Production Partners LP"

Natural Resource Partners, L.P.*

NGL Energy Partners LP

Niska Gas Storage Partners LLC*

NuStar Energy L.P.*

Oiltanking Partners, L.P.*

ONEOK Partners, L.P.

PAA Natural Gas Storage, L.P.*

Penn Virginia Resource Partners, L.P.

Pioneer Southwest Energy Partners L.P.*

Plains All American Pipeline, L.P.*

QR Energy, LP*

Regency Energy Partners LP*

Rose Rock Midstream, L.P.*

Spectra Energy Partners, LP*

Sunoco Logistics Partners, L.P.

Targa Resources Partners LP*

TransMontaigne Partners, L.P.

Vanguard Natural Resources, LLC*

Western Gas Partners, LP*

W.P. Carey & Co. LLC

Williams Partners L.P.