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},
}