Krucoff, M. W., Landis, D. I., Green, C. L., Loeffler, A. K., Eisenstein, E., Moore, A., … Sketch, M. H. (1997). Upright posture with a flexible femoral sheath: Safety and cost results from 900 patients in the ''heads up'' trial. JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, 29(2), 9938–9938.

Krucoff, M. W., D. I. Landis, C. L. Green, A. K. Loeffler, E. Eisenstein, A. Moore, J. E. Tcheng, et al. “Upright posture with a flexible femoral sheath: Safety and cost results from 900 patients in the ''heads up'' trial.” JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY 29, no. 2 (February 1, 1997): 9938–9938.

Krucoff MW, Landis DI, Green CL, Loeffler AK, Eisenstein E, Moore A, et al. Upright posture with a flexible femoral sheath: Safety and cost results from 900 patients in the ''heads up'' trial. JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY. 1997 Feb 1;29(2):9938–9938.

Krucoff, M. W., et al. “Upright posture with a flexible femoral sheath: Safety and cost results from 900 patients in the ''heads up'' trial.” JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, vol. 29, no. 2, ELSEVIER SCIENCE INC, Feb. 1997, pp. 9938–9938.

Krucoff MW, Landis DI, Green CL, Loeffler AK, Eisenstein E, Moore A, Tcheng JE, Califf RM, Mark DB, Morris KG, Sketch MH. Upright posture with a flexible femoral sheath: Safety and cost results from 900 patients in the ''heads up'' trial. JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY. ELSEVIER SCIENCE INC; 1997 Feb 1;29(2):9938–9938.