The transition frequencies were taken from
(1) C. E. Blom and A. Bauder 1981, Chem. Phys. Lett., 82, 492.
This is the lowest energy conformer, which exhibits a hydrogen bond from the alcoholic hydroxyl H atom to the O atom of the carbonyl group.
With one additional, sextic, distortion parameter, all lines could be used in the fit. Almost all of the lines fit exceedingly well, such that few larger deviations were interpreted as 100 kHz typographical errors. Predictions with uncertainties larger than 0.5 MHz should be viewed with caution.
The dipole moment components were determined in (1).