According to a 1970 report on floriculture crop production and flowering
pot plant crops, the year's wholesale value of saintpaulia crops was
$2,088,000. This dollar amount was 0.4% of all floriculture crops. Other
sources you might try are:
Free, Montague. "All About African Violets". Doubleday & Company inc.
Garden City, N Y .1979.
Fogg, H.G. Witham. "Begonia, Gloxinias, and African Violets." John Gifford
Mastalerz, John W. "The Greenhouse Environment". John Wiley & Sons, N Y
Theodore, James Jr. "African Violets." HP Books. Tucson, AZ. 1983.
Wall, Bill. "African Violets and Related Plants. Cassell Educational
Limited. London. 1990
Wilson, Helen Van Pelt. "The Complete Book of African Violets." M. Barrows
and Co., Inc. N Y 1951
----,"African Violet Book." Hawthorn Books Inc. N Y 1970
Cornell Recommendations for Commercial Floriculture Crops, Part I:
Cultural Practices and Production Programs, Cornell U. 1981.
Hope this helps. VRose at ucdavis.edu