Koop, J., & Rutberg, J. (2016). Training essentials for ultrarunning: How to train smarter, race faster, and maximize your ultramarathon performance. VeloPress.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रKoop, Jason, और Jim Rutberg. Training Essentials for Ultrarunning: How to Train Smarter, Race Faster, and Maximize Your Ultramarathon Performance. Boulder, Colorado: VeloPress, 2016.
एमएलए (8वां संस्करण) प्रशस्ति पत्रKoop, Jason, और Jim Rutberg. Training Essentials for Ultrarunning: How to Train Smarter, Race Faster, and Maximize Your Ultramarathon Performance. VeloPress, 2016.
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