original: the film is mainly based on robert drewe 's book our sunshine .
simplifications: the film 's idea came mainly from robert drewe 's book our sunshine . the movie is mostly like robert drewe 's book our sunshine . the film is mostly based on the book our sunshine by robert drewe . the film is mainly based on robert drewe 's book , our sunshine . the source of the film 's storyline is robert drewe 's book " our sunshine . " the film is mainly based on a book " our sunshine " written by robert drewe . the film is mainly based on robert drewe 's book our sunshine . the film is based on robert drewe 's book our sunshine .