@article{IUPAC+P04846+2019,
url = {https://doi.org/10.1351/goldbook.P04846},
institution = {International Union of Pure and Applied Chemistry (IUPAC)},
year = {2019},
title = {principal group},
doi = {doi:10.1351/goldbook.P04846},
edition = {3.0.1}
}