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Originating report, July 1976. NTRS author abstract describes small nearly vertical wing-tip surfaces and wind-tunnel measurements of forces, moments and loads on a representative narrow-body transport wing. Its comparison with a tip extension approximately matches the increment in wing-fuselage-junction bending moment. The article's drag-budget example is original, not a numerical result of this experiment.

Additional exact locators: printed pp. 7–8, Incidence and twist and Cant or dihedral. These distinguish winglet incidence from cant and discuss the tradeoff among induced-drag reduction, skin friction and wing bending moments, including root-flow interference for outward cant. The Winglet cant angle article states its own explicit vertical-reference convention.

NACA-RM-L6J01a,14 February 1947. Abstract: no sweep, ±30 degrees and ±45 degrees; Mach numbers 0.60–0.96; pressure measurements and wake surveys compare shock-associated changes.

NACA-TR-1273 (1956), NTRS document 19930092271. The originating report abstract compares shock phenomena and drag-rise increments for wing/body combinations and equivalent bodies of revolution with matched axial area distributions. Indenting the body to compensate for the wing area reduced the measured zero-lift drag-rise increment. The reported conclusion is conditioned on thin low-aspect-ratio combinations near sonic speed; it is not a universal statement about every shape or Mach number.