Complex sentence: The recordings appear here in Mono, no Stereo versions are know to exsist, in the 1970's Philips did re-issue them in an Electronically Enhanced Stereo (also known as Pseudo-stereo), but these added echoes proved unpopulair and these versions have not been rereleased.
Split into simpler sentences: The recordings appear here in Mono, no Stereo versions are known to exsist. In the 1970's Philips did re-issue them in an Electronically Enhanced Stereo (also known as Pseudo-stereo), but these added echoes proved unpopulair and these versions have not been rereleased.