K. Yamaguchi, K. Akai, G. Kawanishi, M. Ueda, S. Masuda, R. Sasaki,
Effects of site-directed removal of N-glycosylation sites in human erythropoietin on its production and biological properties. Journal of Biological Chemistry. ,vol. 266, pp. 20434- 20439 ,(1991) ,
10.1016/S0021-9258(18)54942-5