Here are some of the papers that we published on frequency enhancement of seismic data

2011: Mixed-phase wavelet estimation – a case study, published in CSEG RECORDER

2010: Phase stability via nonlinear optimization – a case study, published in SEG-The Leading Edge

2004: High-frequency restoration of surface seismic data, published in SEG-The Leading Edge

2004: A new approach to enhancing the bandwidth of surface seismic data, published in EAGE-First Break

2003: Enhancing seismic frequency bandwidth using VSPs – a case study, published in Oil and Gas Journal