I hope these links will help you in your quest for information on the construction of greenhouses. If you find a dead link, please let me know so that I may remove it.
http://www.faculty.sbc.edu/simpson/G...use/Index.html
http://www.irisherbal.com/psg/content/whybuild.html
http://www.igcusa.com/
http://attra.ncat.org/attra-pub/solar-gh.html
http://www.backyardgardener.com/gree...strucition.htm
http://www.aces.edu/pubs/docs/A/ANR-1105/ANR-1105.pdf
http://www.wvu.edu/~agexten/hortcult...u/grencons.htm
http://www.hydroponicsearch.com/cgi-...s%20greenhouse
http://www.sciencecentral.com/product/23686
http://skipjack.net/sfi/construction.html
http://aesop.rutgers.edu/~horteng/fl...ydroponics.htm
http://www.ki7xh.com/greenhouse.htm
http://smallfarms.ifas.ufl.edu/crops...se_design.html
http://aggie-horticulture.tamu.edu/G...economics.html
http://www.sherrysgreenhouse.com/pag...ses-build.html