The best and most complete is Hunnicutt's Pershing.; Feist Publications; $$$ (Or order from your Library)
M-26 Pershing Walk Around; Squadron Signal 5706
M-26/M-46 Pershing Tank 1943-53; New Vanguard by Zaloga (misnamed as M-46 was Patton)
The M-26 Pershing and Variants ; Troy D Thiel Schiffer Publishing Co Berkeley CA

All cover M-26, Super Pershing, M-45, M-46.

The HL and Tammy are Korean Vintage Pershings. Color is pretty close on HL, but still, little changes have to be made and Chinese toymakers ideas have to be discarded if you want it to look like a Pershing.. You don't need another upper chassis...just eliminate the driver-bog aux periscopes, for the most part, remove or fold up the skirts for ammo stowage and toss the front and rear sections. Add fender braces on all 4 corner fenders. Remove the garbage stowed on the back and stand the jerry can up and rope/strap it down to the side on the fender by the tranny near the lifting ring..or stow it in the bracket on the right side of the turret. Do NOT add Tiger face! If you are keeping the skirts, add some "cable" or "weld' a couple brackets and steel strips along the sponson boxes to keep the mg ammo boxes from walking away. Photos of korean War Pershings will show these features.

Hope this helps.
Bill