I. P. Goulden, D. M. Jackson. The enumeration of generalised alternating subsets with congruences. Discrete Mathematics, 22(2):99-104, 1978. [doi]
@article{GouldenJ78, title = {The enumeration of generalised alternating subsets with congruences}, author = {I. P. Goulden and D. M. Jackson}, year = {1978}, doi = {10.1016/0012-365X(78)90118-8}, url = {http://dx.doi.org/10.1016/0012-365X(78)90118-8}, researchr = {https://researchr.org/publication/GouldenJ78}, cites = {0}, citedby = {0}, journal = {Discrete Mathematics}, volume = {22}, number = {2}, pages = {99-104}, }