Here is a website that goes through oldgas and you can buy the gas globe book vol 1 and 2 or blue and pink as most of us know them by. gaspumps.infogasglobes.com
and Scott wrote the books mention above.
Best thing to do is watch ebay! Look at gasglobes.com and see what Scott post and sells. Go to gas shows and look at globes there. Look at repops.
Best thing to do is get to know other globe collectors and ask for there help! Most of use have asked for help and give help.