The optical calcium frequency standard. - Fritz Riehle; Harald Schnatz; Burghard Lipphardt; Götz Zinner; Tilmann Trebst; Jürgen Helmcke (IEEE Trans. Instrum. Meas., 1999)

A novel stabilization method for an optical frequency comb generator. - Uwe Sterr; Burghard Lipphardt; Andreas Wolf; Harald R. Telle (IEEE Trans. Instrum. Meas., 1999)

Optical frequency measurements using fs-comb generators. - Harald Schnatz; Burghard Lipphardt; Carsten Degenhardt; Ekkehard Peik; Tobias Schneider; Uwe Sterr; Christian Tamm (IEEE Trans. Instrum. Meas., 2005)

171Yb+ Single-Ion Optical Frequency Standard at 688 THz. - Christian Tamm; Burghard Lipphardt; Harald Schnatz; Robert Wynands; Stefan Weyers; Tobias Schneider; Ekkehard Peik (IEEE Trans. Instrum. Meas., 2007)

The Stability of an Optical Clock Laser Transferred to the Interrogation Oscillator for a Cs Fountain. - Burghard Lipphardt; Gesine Grosche; Uwe Sterr; Christian Tamm; Stefan Weyers; Harald Schnatz (IEEE Trans. Instrum. Meas., 2009)

Microwave Synthesis for the PTB Cesium Fountain Clocks. - Michael Kazda; Vladislav Gerginov; Burghard Lipphardt; Stefan Weyers (IEEE Trans. Instrum. Meas., 2020)