Bad recommendations here. Cooking pork ribs between 135F and 160F oven temperature for hours, eaters will gnaw on tough ribs at best, or heave and poop into a toilet for days at worst (presuming survival). What kind of cook would write this????? Extended exposure to a temperature of at least 200F is necessary for tender meat. Any restaurant which subjects meat to just 135F would face health-code violations and food-poisoning liability.
".......The lower the meat’s temperature, the less moisture it loses, but the longer its connective tissue takes to dissolve, too. You can get very juicy ribs by cooking them at 135 degrees, but making them tender takes two or three days. At 160 degrees, you get tender ribs in 10 to 12 hours. At 170 to 180 degrees, the meat is noticeably dryer, but the cooking time is a more manageable 6 to 8 hours...."