  As evidenced by recent survey results, majority of asteroids are slow
rotators (P>12 h), but lack spin and shape models due to selection bias. This
bias is skewing our overall understanding of the spins, shapes, and sizes of
asteroids, as well as of their other properties. Also, diameter determinations
for large (>60km) and medium-sized asteroids (between 30 and 60 km) often vary
by over 30% for multiple reasons.
  Our long-term project is focused on a few tens of slow rotators with periods
of up to 60 hours. We aim to obtain their full light curves and reconstruct
their spins and shapes. We also precisely scale the models, typically with an
accuracy of a few percent.
  We used wide sets of dense light curves for spin and shape reconstructions
via light-curve inversion. Precisely scaling them with thermal data was not
possible here because of poor infrared data: large bodies are too bright for
WISE mission. Therefore, we recently launched a campaign among stellar
occultation observers, to scale these models and to verify the shape solutions,
often allowing us to break the mirror pole ambiguity.
  The presented scheme resulted in shape models for 16 slow rotators, most of
them for the first time. Fitting them to stellar occultations resolved previous
inconsistencies in size determinations. For around half of the targets, this
fitting also allowed us to identify a clearly preferred pole solution, thus
removing the ambiguity inherent to light-curve inversion. We also address the
influence of the uncertainty of the shape models on the derived diameters.
  Overall, our project has already provided reliable models for around 50 slow
rotators. Such well-determined and scaled asteroid shapes will, e.g. constitute
a solid basis for density determinations when coupled with mass information.
Spin and shape models continue to fill the gaps caused by various biases.
