Book  (2013)  Page(s) 106.  
 
Eric Timewell. I am German. Frank Riethmuller’s Breeding:
The Australian film Jedda came out in 1955 when Riethmuller was 71. In the film, Jedda, a black girl raised as a white Anglo-Saxon, gazes into the bush and utters words that could have been Riethmuller’s own:
It’s time my people came back from their walkabout. You know… sometimes I dream I’m out there with them… they are my people… I should go walkabout and learn the customs of my tribe.
It added piquancy that the film’s aboriginal star had a German surname: Ngarla Kunoth. Riethmuller’s rose ‘Ngarla’ came out in the same year as the film. It is perhaps the Riethmuller rose whose loss is to be most regretted. George Knight’s ‘Nigger Boy’ was “blackish maroon,” Alister Clark’s ‘Black Boy’ is dark red and Olive Fitzhardinge’s ‘Lubra’ is even darker. We can be sure 'Ngarla' was a very dark red.

Magazine  (2012)  Page(s) 41. Vol 34, No. 2.  
 
Eric Timewell. Frank Riethmuller’s Niece Elsie:
Most [roses] survived because Elsie took them to Toowoomba….At this point it became all too easy for her to leave behind the humiliation of those roses dedicated to women. At least seven Riethmuller roses of all sorts ‘Ngarla’ and…. disappeared from view, in most cases never to be seen again.

Newsletter  (1995)  
 
Vol 4-4. Summer. p18.

Ngarla H. Poly 1955 F. L. Riethmuller.

Book  (1960)  Page(s) 102.  
 
Mr. Francis L. Riethmuller who receives the coveted award (the T. A. Stewart Memorial Award for 1959) has devoted much time and energy to roses since his retirement, fifteen years ago. He has done much hybridising and has distributed some very worthy varieties, as well as lesser-known varieties such as ...... and Ngarla.

Book  (1955)  Page(s) 128.  
 
New Rose Registrations: No. 139. Ngarla. Hyb. Pol. F. L. Riethmuller. January 1, 1955