Can Case Law be cited in a complaint?

There is usually no need to cite case law citations in a complaint.

In Texas, yes; but I'm not licensed in California. Pleading practice generally allows a plaintiff/petitioner/applicant to generally state his/her claim and follow it with something like: "... as required by Section (article, etc.) _____ of the California _______ Code (or other citation to the specific law). In CRIMINAL complaints, the answer is also "yes," in Texas, and it's frequently done.

I am not licensed to practice in California, so you will want to check with a California lawyer. Please also consider checking with a lawyer in your district to determine whether there are local rules that pertain to the manner in which you sould create and file complaints. Generally, a complaint states your claim, and if a statute or case provides the authority for your cause of action, it is acceptable to cite these. However, the complaint is generally not the place for argument, and if that is the reason you wish to cite the case, it is probably not a wise choice. If it's a clear and well-used case, such as "Miranda v. Arizona", for example, and you were filing for a violation of your civil rights, one of your clauses might be that you were not read your rights under the case of Miranda v. Arizona at the time of your arrest and questioning. You are not giving an argument that Miranda means this or that, just that Miranda was not followed, and if the person you're suing disagrees, they can respond that they disagree. Think of it this way, you want to state a complaint as simply and clearly as possible so that the other person can see it and say, "gee, I really do owe that money" or, "I need to challenge this", after which you can get into arguing whether or not a particular case applies. If you start out with an argument, it is less likely to settle, and the courts prefer amicable settlement over acrimonious arguments, nearly every time.

In California, such as the U.S. District Court for the Central District of California where you will likely be filing your complaint, it is rare to cite any case in a complaint. Citations are used for legal argument in motions. Citations are not necessary in complaints or in answers. However, once in a while, we do see a case citation in the allegations of a complaint if it helps explain the claim being asserted in the claim for relief.