Adding equations and citations on PR checklist
Adding equations and citations on PR checklist

rafaelmds/fatiando,cmeessen/fatiando,eusoubrasileiro/fatiando,rafaelmds/fatiando,fatiando/fatiando,santis19/fatiando,mtb-za/fatiando,victortxa/fatiando,eusoubrasileiro/fatiando_seismic,drandykass/fatiando,eusoubrasileiro/fatiando,victortxa/fatiando,eusoubrasileiro/fatiando,eusoubrasileiro/fatiando_seismic,fatiando/fatiando,cmeessen/fatiando,mtb-za/fatiando,santis19/fatiando,drandykass/fatiando