by Tobias Heindel and Paweł Sobociński
Reference:
Tobias Heindel and Paweł Sobociński, Being Van Kampen is a universal property, In Log. Methods Comput. Sci., vol. 7, no. 1, 2011.
Bibtex Entry:
@article{Heindel2011,
author = {Tobias Heindel and Pawe{\l} Soboci{\'{n}}ski},
title = {Being {V}an {K}ampen is a universal property},
journal = {Log. Methods Comput. Sci.},
volume = {7},
number = {1},
year = {2011},
doi = {10.2168/LMCS-7(1:14)2011},
url = {https://doi.org/10.2168/LMCS-7(1:14)2011},
}