Book  (Apr 1993)  Page(s) 227.  
 
Grumpy Polyantha, pink, 1956, ('Burkhardt'); Parentage unknown; deRuiter. Description.

Book  (Jun 1992)  Page(s) 242.  
 
Mentioned as one of the "7 Dwarfs" series.

Book  (1991)  Page(s) 243.  
 
Burkhard Polyantha. ('Grumpy') De Ruiter, 1956. Pink.

Book  (1958)  Page(s) 146.  
 
Grumpy (Burkhard in Germany). Pol. (de Ruiter; int. Gregory and Willicher Baumschulen, '56.) Parentage unknown. Small, dbl., pink; long truss.