“…These guidelines were most frequently in the form of a handbook or published paper (N = 31) [2,4,9,15,20,25,28,29,31,36,37,41,50,64-67,69,80,84-87,89,90,95,100,116], whereas in 14 critical appraisal tools explanations accompanied each item [16,26,27,40,49,51,57,59,79,83,91,102]. …”