References are

Wisniewski (1989b)

Ruled Fano 4-folds of index 2

Szurek-Wisniewski (1990b)

Fano bundles over and $Q^3$.

Szurek-Wisniewski (1990c)

Fano bundles of rank 2 on and $Q_3$.

where is del Pezzo threefold of degree 5.

Regularized I-series for V is

Nonregularized

For line $I_{P^1} = \sum_n \t^{2n} \frac{1}{n!^2}$

For product fourfold we have

So for threefold section X we have to change t^2 to t and do Laplace transform once (for non-regularized):

Regularizing gives

After normalization this gives period sequence 39: