G. D. Gale et al., "The Bartlett-Edwards Incentive Spirometer: A Preliminary Assessment of its Use in the Prevention of Atelectasis After Cardio-Pulmonary Bypass", Canad. Anaesth. Soc. I, vol. 24, No. 3, May 1977, pp. 408-416. |
"The Challenger Incentive Spirometer Measures Volume, Not Flow", Advertisement in American Hospital Supply, May/Jun. 1980, p. 4. |
"VOLUREX Opens a New Era in Volume Measured Respiratory Exercise", one page magazine advertisement, date uncertain but thought to be Jan./Feb. 1980. |
"U-MID/VOLUME PLUS Respiratory Exerciser", two page magazine advertisement, date uncertain but thought to be Jan./Feb. 1979. |
U.S. patent application Ser. No. 87,288, "Incentive Breathing Exerciser", Victor L. Poirier, filed Oct. 22, 1979. |