  A multiset hook length formula for integer partitions is established by using
combinatorial manipulation. As special cases, we rederive three hook length
formulas, two of them obtained by Nekrasov-Okounkov, the third one by Iqbal,
Nazir, Raza and Saleem, who have made use of the cyclic symmetry of the
topological vertex. A multiset hook-content formula is also proved.
