How to add noise to EEG signal

I want to add noise to the EEG signal, but I need some paper reference, I mean how researchers add noise to the signal. I want to test my methodology robustness incase of noise

I am adding noise like this

mu, sigma = np.mean(data), np.std(data)
noise = np.random.normal(mu, sigma, data.shape)

Its gaussian noise with mean and std equal to mean and std of data. But I need some reference for it.