I need a thorough online site or downloadable text that goes into detail about English phrase markers as in this example from Beth Levin's Verb Alternations book "This alternation involves verbs found in two frames in a near-paraphrase relationship: NP1 V[pp P NP2]' and '[np NP1 and NP2] V apart]" where and and apart are actual words and not slots to be filled.
This looks like phrase markers from generative grammar, but I don't necessarily need the text to be linguistic theory specific, although it would be okay if the text or site did go into detail about how academicians proposing different theories use phrase markers in their work.
I am building an NLP software tool and will need to incorporate these markers into the code. Thanks in advance to any answers. All will be useful.