Volume 3, Part 2, pp. 157 - 261 (1955)
Volume 2, Part 1, pp. 1- 68 (1952)
BLUMEA 32 (1987) 39-65
Proceedings of the Academy of Natural Sciences of Philadelphia, 142:21-58, 1990
Acta Bot. Neerl. 28 (2/3), May 1979. p. 117-155
EDINBURGH JOURNAL OF BOTANY VOLUME 47 NO. 1 1990
NOTES FROM THE ROYAL BOTANIC GARDEN EDINBURGH VOLUME 31 NO.2 JANUARY 1972