Olson, L. D. (1996). Nondestructive testing of unknown subsurface bridge foundations: Results of NCHRP Project 21-5. Transportation Research Board, National Research Council.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Olson, Larry D. Nondestructive Testing of Unknown Subsurface Bridge Foundations: Results of NCHRP Project 21-5. Washington, D.C: Transportation Research Board, National Research Council, 1996.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Olson, Larry D. Nondestructive Testing of Unknown Subsurface Bridge Foundations: Results of NCHRP Project 21-5. Transportation Research Board, National Research Council, 1996.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.