On the crossing numbers of products of cycles and graphs of order four
Lowell W. Beineke, Richard D. Ringeisen · Journal of Graph Theory · 1980
Abstract The main results are that the crossing number of the product C4 × Cn is 2n for n ≥ 4 and that of the product K4 × Cn is 3n for n ≥ 3. These are extensions of an earlier result giving the crossing number of C3 × Cn as n for n ≥ 3.