1 INTRODUCTION  
2 FORMALISM  
3 AUTO CORRELATION FORECASTS FOR [CII] AND [OIII]  
4 CROSS-CORRELATING A GROUND-BASED [CII] AND A BALLOON-BASED [OIII] SURVEY  
5 AN ‘IDEAL’ [OIII] AND [CII] INTENSITY MAPPING SURVEY?  
6 CONCLUSIONS  