Spring, I., & Manning, H. (1974). Wilderness trails Northwest: A hiker's and climber's overview-guide to national parks and wilderness areas in Wyoming, Montana, Idaho, Northern California, Oregon, Washington, British Columbia, Canadian Rockies. Touchstone Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रSpring, Ira, और Harvey Manning. Wilderness Trails Northwest: A Hiker's and Climber's Overview-guide to National Parks and Wilderness Areas in Wyoming, Montana, Idaho, Northern California, Oregon, Washington, British Columbia, Canadian Rockies. Beaverton, Or.: Touchstone Press, 1974.
एमएलए (8वां संस्करण) प्रशस्ति पत्रSpring, Ira, और Harvey Manning. Wilderness Trails Northwest: A Hiker's and Climber's Overview-guide to National Parks and Wilderness Areas in Wyoming, Montana, Idaho, Northern California, Oregon, Washington, British Columbia, Canadian Rockies. Touchstone Press, 1974.