1. Introduction  
2. Observations and Spectral Morphology  
2.1. Sample Selection  
2.2. Data Acquisition and Reduction  
2.3. K-band Magnitudes  
2.4. Continua  
2.5. Spectral Composition  
3. Spectral Modeling  
3.1. Pfund Model  
3.2. CO Model  
3.3. Model Results  
4. Discussion  
4.1. LBVs  
4.2. Incidence of CO Emission in B[e]SGs  
4.3. Influence of Rotation on Stellar Mass Loss  
4.4. Evolutionary Connection between Transition Objects  
5. Conclusions