I guess so, I found the books on Internet, links attached.

https://www.dropbox.com/s/s8emli89302smr1/John%20Ehlers%20-%20Signal%20Analysis%2C%20Filters%20And%20Trading%20Strategies.pdf?dl=0
https://www.dropbox.com/s/1t5h59cp9fttpfb/sp4comm_corrected.pdf?dl=0