4AMASORRAIN J I, SAGARTZAZU X, DAMIAN J. Load distribution in a four contact-point slewing bearing. Mechanism and Machine Theory, 2003,38:479 - 496.
5ZUPAN S, PREBIL I. Carrying large single row ball bearing as angle and carrying capacity of a a function of geometry parameters of the rolling contact and the supporting structure stiffness [ J ]. Mechanism and Machine Theory, 2001,36 : 1087 - 1103.