Requesting comic book referrals - Harley Quinn & Joker

[Nerwign]

Hi there! I have a friend who lives in Japan and loves Harley Quinn / Joker stories but she has a hard time finding US comic books where she lives. I'd like to buy some for her as a gift but am clueless as to what to buy. Can someone give me some good recommendations for comic books/collections she might like?


PS
I already bought her this book and she liked it a lot:
Batman: Harley Quinn Paperback – July 21, 2015
by Paul Dini (Author), Neil Googe (Illustrator)

She also just picked this up and liked it but it was expensive and she couldn't pre-view the art or story before purchase so it felt like a gamble at the time:
Batman: Hush Paperback – August 18, 2009
by Jeph Loeb (Author), Jim Lee (Illustrator)

[batnbreakfast]

Gotham City Sirens Book One (Paul Dini)

Harley and Ivy: The Deluxe Edition (Paul Dini)

Harley Quinn Preludes and Knock Knock Jokes (Karl Kesel)


Amazon makes it easy to pick those up but I can't remember how big Joker's part is, they should be focusing on Harley

EDIT: Dark Night: A true story is about a mugging that happened to Paul Dini (Harley's creator) in real life and how inventing Harley helped him to cope with that

[JAG2045]

The whole 38 issue Harley Quinn series from 2000-2004 is available in the following TPB's:

Vol. 1: Preludes and Knock-Knock Jokes (1-7)
Vol. 2: Night and Day 8-13 & Harley Quinn Our Worlds at War 1
Vol. 3: Welcome to Metropolis 14-25
Vol. 4: Vengeance Unlimited 26-38

If its easier your friend could also buy them digitally on readdcentertainment or comixology (which would save on shipping to!) Here's the 2000 series https://www.readdcentertainment.com/...s-series/10177