"Respiratory Tract Diseases epidemiology United States Statistics." . . "Office Visits utilization United States Statistics." . . . . . . . . . . . . . . . "Office visits for respiratory conditions : National Ambulatory Medical Care Survey, United States, 1975-76"@en . . . "Office visits for respiratory conditions National Ambulatory Medical Care Survey, United States, 1975-76"@en . . . . . . "Statistics"@en . "Ambulatory Care utilization United States Statistics." . . "Physicians utilization United States Statistics." . .