Celik, Y., Peker, K., & Oguz, C. (2010). Comparative Analysis of Energy Efficiency in Organic and Conventional Farming Systems: A Case Study of Black Carrot (Daucus carota L.) Production in Turkey. Philippine Agricultural Scientist, The (Formerly the Philippine Agriculturist).

Celik, Yusuf, Kenan Peker, and Cennet Oguz. "Comparative Analysis of Energy Efficiency in Organic and Conventional Farming Systems: A Case Study of Black Carrot (Daucus Carota L.) Production in Turkey." Philippine Agricultural Scientist, The (Formerly the Philippine Agriculturist) 2010.

Celik, Yusuf, et al. "Comparative Analysis of Energy Efficiency in Organic and Conventional Farming Systems: A Case Study of Black Carrot (Daucus Carota L.) Production in Turkey." Philippine Agricultural Scientist, The (Formerly the Philippine Agriculturist), 2010.