Book  (Oct 2001)  Page(s) 132-133.  Includes photo(s).
 
Clematis 'Blue Dancer'
Atragene Group
(C. alpina 'Blue Dancer')
Raymond Evison (England) late 1980s
... single, nodding, pale blue flowers... four narrow, twisiting, pointed tepals, each 5-7.5 cm (2-3 in.) long... Short, pale creamy green, spoon-shaped, petal-like staminodes...

Book  (Apr 1998)  Page(s) 92.  
 
C. alpina 'Blue Dancer'
... very pale blue flowers
... mid to late spring
... height 3 m (10 ft)