A great technical article by Morion Inc, Russia that was published in the May 2015 issue of Microwave Journal.

A new precision 10 MHz oven controlled crystal oscillator (OCXO) exhibits low phase noise close to the carrier (-120 dBc/Hz at 1 Hz) and a low noise floor (-160 dBc/Hz at 1 kHz) with very good frequency versus temperature stability.

Please read the entire article HERE.