Seed Quest - http://www.seedquest.com
Vegetable Seed Companies - http://hort-devel-nwrec.hort.oregonstate.edu/seedlist.html
Smithsonian Institution - http://www.sil.si.edu/SILPublications/seeds/seedsmanbios.html
University of Rochester, NY: Ellwanger & Barry Prints Produced in Rochester and Elsewhere - http://www.library.rochester.edu/index.cfm?page=861
“Nineteenth-Century Rochester Fruit and Flower Plates”, by Karl Sanford Kabelac, University of Rochester Library Bulletin, XXXV, 1982 - http://www.lib.rochester.edu/index.cfm?page=2397
“Joseph Harris: Captain of the Rochester Seed Industry”, by Karl Sanford Kabelac, University of Rochester Library Bulletin, XXXV, 1982 - http://www.lib.rochester.edu/index.cfm?PAGE=2400
“Petunias by Post: The Post Office and America’s 19th century Horticultural Boom”, by Dr. Cheryl Lyon Jenness (Winton M. Blount Symposium on Postal History, Nov. 4, 2006) - http://www.postalmuseum.si.edu/blount/papers/Lyon-Jenness.PDF
Colonial Williamsburg, VA - http://www.history.org/history/CWLand/resrch1.cfm
W. Atlee and David Burpee - http://www.burpee.com/contentarticle.do?itemID=579
All-America Selections - http://www.all-americaselections.org/History.asp
Biographies in Ornamental Horticulture - http://members.tripod.com/~Hatch_L/bioh.html