"Proceedings-Special issue on time and frequency. Vol.27, No.10, Part I, October 1981"
"INTERNATIONAL SYMPOSIUM ON TIME & FREQUENCY (National Physical Laboratory, New Delhi) February 10-12, 1981"
"Proceedings-Special issue on time and frequency. Vol.27, No.10, Part I, October 1981" - New Delhi IETE 1981 - irreg p.
"Proceedings-Special issue on time and frequency. Vol.27, No.10, Part I, October 1981" - New Delhi IETE 1981 - irreg p.