(1)
(2) Theodore Grey
(3)
(4) Northwestern University, DVAction
(5)
(6) University of Illinois at Urbana-Champaign
(7) Monterey Peninsula College, Mark Bishop
(8) Sam Houston State University, Thomas G. Chasteen
(9) TORVS Research Group, University of Erlangen, Germany
(10) South Dakota School of Mines and Technology,
Chemistry Outreach 2000
(11)
(12) YouTube extract from BBC/OU program "Elements Organised: A Periodic Table".
(13) Central Michigan University Stockroom
(14)
(15) Indiana State University, Terre Haute, Laurence
Rosenhein and Phil DiLavore
(16) Chemland, University of Massachusetts, William Vining
(17) Prentice Hall, Inc.
(18) YouTube extract from the UK Brainiac series
(19)
(20)
(21)
(22) University of Regensburg, Peter Keusch