- Conti, Phytopath. Z. 66: 275, 1969.
- Hills & Campbell, J. Ultrastruct. Res. 24: 134, 1968.
- Howatson, Adv. Virus Res. 16: 196, 1970.
- Hull, in Biology of Large RNA Viruses, ed. R. D. Barry & B. W. J. Mahy, Academic Press, N.Y., 1970.
- Lin & Campbell, Virology 48: 30, 1972.
- McLean & Francki, Virology 31: 585, 1967.
- Tomlinson & Webb, Rep. natn. Veg. Res. Stn 1970: 110, 1971.
- Tomlinson, Webb & Faithfull, Ann. appl. Biol. 71: 127, 1972.