1. Abdullah AA, Yeoman MM, Grace J (1985) In vitro adventitious shoot formation from embryonic and cotyledonary tissues of Pinus brutia Ten. Plant Cell Tissue Org Cult 5:35–44
2. Ahuja MR (1983) Somatic cell differentiation and rapid clonal propagation of Aspen. Silvae Genet 32:131–135
3. Ahuja MR (1984) In vitro induction of organogenesis in juvenile and mature beech. Silvae Genet 33:241–242
4. Ammirato PV (1983) The regulation of somatic embryo development in plant cell cultures: Suspension culture techniques and hormone requirements. Biotech 1:68–74
5. Becwar MR, Noland TL, Wann SR (1987 a) Somatic embryo development and plant regeneration from embryogenic Norway spruce callus. Tappi 70:155–160