Because PQ Angels was a follow up to Takeuchi Naoko's widely successful and popular Bishoujo Senshi Sailormoon, she placed several sightings of the sailormoon kind within the short acts of PQ Angels. Here they are, in order:
Act 1, Page 6 - A little girl at the airport is reading the Bishoujo Senshi Sailormoon Tankoubon Volume 7, (specifically act 23, page 6). Peanut, in cockroach form reads over her shoulder and is upset when the little girl's mother calls to her and she can no longer read it. She says "just when it got to the good part!" and draws attention to herself (both Ouji and Miki, the little girl with the manga hear her). Interesting to side-note, according to the Alex Glover translations, she misreads "Queen Selenity" as "Queen Seleniny" because she is still learning her katakana.
Act 3, Page 7 - Ouji sees the girls flying into the full moon and says "why do they look like the rabbit of the moon from behind?" A reference to the pun in Tsukino Usagi's (the main heroine of Sailormoon) name, which could be translated literally to "rabbit of the moon". It is also a familiar folk tale from Buddhism in Japan.
Act 3, Page 15 - Upon returning from Furien, Piiko announces that she smells something sweet. Kyuuko explains that it is a flower- fragrant olives. Fragrant Olives is the scent the Sailor Starlights were looking for in the Bishoujo Senshi Sailormoon anime and manga to find Princess Kakyuu. This occurs in the final, or Stars, season of the anime and in the final arc of the BSSM manga.
Act 3, Page 21 - Kuria says that only someone from another planet would say their ideal boyfriend is a prince after Piiko says she wants to have a romance with a prince. Then she wonders if Piiko could be the "Princess of the Moon". This is in reference to Sailormoon because the main character is indeed the princess of the moon. It is also a reference to the Tale of Princess Kaguya, a commonly known folk tale about a bamboo cutter who adopts the princess of the moon.
Act 3, Page 29 - During the Koganemushi festival (an athletic festival) at school, two girls are cosplaying in Bishoujo Senshi Sailormoon outfits. Koganemushi is a type of beetle, which is fitting because, after all, so are cockroaches. The two girls are standing next to Baigon and Demilin, the beer drinking sisters and villians for this act of the manga.