Book  (1936)  Page(s) 117.  
 
Burke (Portland) Mor. & Rob. 1860; slaty lilac.

Book  (1899)  Page(s) 29.  
 
Burke, Portland, Rob.-Mor., 1860 lilas ardoisé

Website/Catalog  (1880)  Page(s) 250.  
 
Rosiers Portland ou Perpétuels, Rosa Portlandica
844 Burke.—Moyenne ou grande, pleine, plate, lilas ardoisé.

Magazine  (May 1861)  Page(s) Annex, p. 20.  
 
Newest Roses. Recommended from Paris and supplied both by Eugene Verdierr fils ainé, as well as Victor Verdier père et Ch. Verdier fils per May 1st: Everblooming Portland. Burke (Robert et Moreau): medium size, full, flat, lilac.

Magazine  (Dec 1860)  Page(s) Annex, p. 48.  
 
[From an announcement of Eug. Verdier on new roses]. Everblooming Portlands. Burck (Rob. et Mor.): large, full, flat, lilac or pink-lilac. 20 Francs.