Bernal, M. S. M. (2013). Productivity and competitiveness determination of the small-scale mining at the northern mining district in the state of Boyacá. Universidad Pedagógica y Tecnológica de Colombia.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रBernal, Martha Stella Martínez. Productivity and Competitiveness Determination of the Small-scale Mining at the Northern Mining District in the State of Boyacá. Universidad Pedagógica y Tecnológica de Colombia, 2013.
एमएलए (9वां संस्करण) प्रशस्ति पत्रBernal, Martha Stella Martínez. Productivity and Competitiveness Determination of the Small-scale Mining at the Northern Mining District in the State of Boyacá. Universidad Pedagógica y Tecnológica de Colombia, 2013.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.
