The Unix operation system / Kaare Christian, Susan Richter
Quadro comunitário de apoio a Portugal : relatório anual / Direcção Geral do Desenvolvimento Regional
IEEE STD 1139-1999 [documento electrónico] : IEEE Standard Definitions of Physical Quantities for Fundamental Frequency and Time Metrology: Random Instabilities / The Institute of Electrical and Electronics Engineers
IEEE standard 1309-1996 [documento electrónico] : IEEE standard for calibration of electromagnetic field sensors and probes, excluding antennas, from 9 kHz to 40 GHz / Institute of Electrical and Electronics Engineers