1. Initiation of microspore embryogenesis by stress
2. Anther development: basic principles and practical applications.
3. Twell , D.Pollen Developmental Biology. Plant Reproduction; O'Neill , S. D. Roberts , J. A. , Eds. xsl:apply-templates mode="copyref"/> ; Sheffield Academic Press : Sheffield , 2002 , Vol. 6 , 86 – 153 .
4. The remarkable biology of pollen.