Book  (Oct 2001)  Page(s) 175.  Includes photo(s).

Book  (11 Oct 2000)  Page(s) 9.  Includes photo(s).
 
Clematis 'Elsa Späth'

Book  (1999)  Page(s) 235.  
 
...lavender blue flowers with dark red anthers on white filaments...

Magazine  (28 Jul 1937)  Page(s) 56.  
 
TWENTY BEST LARGE-FLOWERED HYBRIDS OBTAINABLE IN THIS COUNTRY
Elsa Späth,  bright blue, Lanuginosa Type
All bloom on new wood except Belle of Woking and Sir Garnet Wolseley