Not all of the photos posted above are of Panther turret pillboxes, the last two are whole Panther wrecks, dug into the street, with dirt and cobblestones piled around the hull.
Trojca's Panther Variants in Color has 5-view scale drawings of a Pantherturm Stahlunterstand.
Another book on the subject is Tank Turret Fortifications by Neil Short, 224 pages with 200 black & white photographs and diagrams. ISBN: 1 86126 687 1.
There was also a Panzertracts publication on Pantherturms, but it must be out of print, as I can't find it on their website. As I recall, it also described Pantherturms on concrete and even wooden platforms.
Osprey's German Defences in Italy in World War II has several photos, including the cover, plus a full color, cut-away diagram of a Panther turret pillbox. Many of the Pantherturm in Italy had 1-meter thick concrete collars around the steel box as added protection.
Here are a whole pile of photos, including some plans;
http://forum.valka.cz/viewtopic.php/p/59008