Based on the style number , you are likely looking at a pattern from Megan Nielsen Patterns , specifically the Jamela Jumpsuit and Dress pattern (the "39" is likely a typo for "MN" or part of a specific retailer code, as Megan Nielsen patterns are often styled this way).
The book is famous for its luminous watercolors and energetic illustrations that capture the "rhythmical musical language" of the region. Finding a "PDF" Version Jamela's Dress - MAG Online Library jamela 39-s dress pdf