Problematic galleries are a global problem. I decided to ensure that I enter all business relationships with a contract after one of my art school tutors was scammed by a London gallery which closed down owing him £80,000 for work they had sold during his solo show!
Here in the UK I find that most professional commercial galleries will send you a copy of their artist terms and conditions when they ask you to show with them.
For those galleries that don't have one (and this is a warning to you about the sort of person you are dealing with!) I protect myself by writing up a contract detailing responsibilities for the gallery and the artist including: how images of the work are to be used, acceptable discounts, responsibility for insurance in transit and in the gallery, the condition of the work on delivery, the agreed retail price for each work, the commission rate, and my payment terms (eg within x days of the show closing/dealer accepting the buyers money) including my bank account details to encourage direct payments.
I always ask a gallery representative to sign a delivery note for work taken on consignment.