@Article{angeo-18-1635-2000,
AUTHOR = {Gupta, J. K. and Singh, L.},
TITLE = {Long term ionospheric electron content variations over Delhi},
JOURNAL = {Annales Geophysicae},
VOLUME = {18},
YEAR = {2000},
NUMBER = {12},
PAGES = {1635--1644},
URL = {https://angeo.copernicus.org/articles/18/1635/2000/},
DOI = {10.1007/s00585-001-1635-8}
}