Given the task definition and input, reply with output. In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: BookWars is a creative documentary which is told in an unconventional, narrative style. The film opens with the narrator (who is also the film's director) driving out West along a desert highway, relating to the audience his previous experiences as a streetside bookseller in New York City. The entire documentary – including the central events involving his experiences among the street booksellers in New York – is thus "told" as a long conversation.
The narrator describes his post-graduation years in New York, and how he ended up at one point virtually penniless. Driven by a desperate need to pay the rent, he resorts to wheeling his own books out to the street to try to sell them. He reveals that he was not only successful in making a significant amount of cash on that first day, but he has also met a variety of interesting and strange characters of the streets of New York – including other street booksellers.
A motley assortment of street booksellers on West 4th street, in Greenwich Village, New York City, are first introduced. Among them: "Slick" Rick Sherman, a semi-professional magician; Al Mappo, so named because he only sells maps and atlases; Emil, who says only he "escaped", though we do not know from where; and Pete Whitney: King of the booksellers, toad collector, and collage artist.
BookWars next introduces another group of street booksellers who hawk their trade on nearby 6th Avenue. Mainly black and minority individuals, they ply books and magazines in parallel fashion to the nearby West 4th street booksellers, who are primarily white. The booksellers on 6th Avenue suffer greater exposure to the law, with many claiming this to be due to racial profiling.
Some of the significant personalities that are introduced on 6th Avenue include: Marvin, always wearing his trademark black hat; and Ron, from Jamaica – charismatic, streetwise and outspoken.
What are the first names of the motley assortment of street booksellers that are introduced?