W. W. Zhu

The NANOGrav 11 Year Data Set: Pulsar-timing Constraints on the Stochastic Gravitational-wave Background

P. S. Ray, V. M. Kaspi, D. R. Lorimer, 2018, 1801.02617.

Periodicity of flare index revisited using the Hilbert–Huang transform method

W. W. Zhu, P. X. Gao, Hong-Fei Liang, 2011 .