notch filter in R

Hi everybody,

I am dealing with a time series of eeg data and I need to filter them 
with a notch filter. However, I could only find the function notch() in 
the RTisean package. Unfortunately, this function is not implemented 
yet. Is there another package/function in R which performs such a filtering?

Thanks in advance for your help.

With best regards,

Soeren Groettrup