Temperature Variations from HST Imagery of NGC 7009
Proceedings article published in 2000 by
R.~H Rubin,
N. Bhatt,
R.~J Dufour,
B. Buckalew,
M.~J Barlow,
X. Liu,
P.~J Storey,
B. Balick,
G.~J Ferland 
,
J.~P Harrington,
P.~G Martin
,
J.~P Harrington,
P.~G Martin
