Key points are not available for this paper at this time.
Anna M. Koltunow, Jessie Truettner, Kathleen H. Cox, Marco Wallroth, Robert B. Goldberg, Different Temporal and Spatial Gene Expression Patterns Occur during Anther Development, The Plant Cell, Vol. 2, No. 12 (Dec., 1990), pp. 1201-1224
Koltunow et al. (Sat,) studied this question.