Submanifolds with flat connection of normal bundle in a riemannian manifold of quasi constant curvature 拟常曲率黎曼流形中的法联络平坦子流形
2.
Specification for low - voltage switchgear and controlgear for industrial use - size numbers and gauges for flat connections 工业用低压开关设备和控制装置规范.扁平连接件的尺寸号和量规
