A Study on the Content of N,P,K in the Leaves and Fruit of Spur type Apple
Liu He, Yang Peifang, Gu Runze, Luo Jianxia, Gao Meiying
ACTA AGRICULTURAE BOREALI-SINICA . 1997, (3): 125 -129 .  DOI: 10.3321/j.issn:1000-7091.1997.03.024