PLCKESZ G008.30-64.75, X-ray source in the field. Redshift quoted in Abell et al.(1989), ApJS 70, 1 and in Martini et al.(2007), ApJ, 664, 761.
PLCKESZ G049.20+30.86, In ERCSC at 545 and 857 GHz. Possible contamination could affect Y estimate. 
PLCKESZ G053.44-36.26, In ERCSC at 545 GHz. Possible contamination by source emission could affect Y estimate. Redshift quoted in Smail et al.(2007), ApJ, 654, L33
PLCKESZ G055.97-34.88, Possible contamination by dust emission could affect Y estimate.
PLCKESZ G062.42-46.41, Possible contamination by dust emission could affect Y estimate.
PLCKESZ G072.80-18.72, X-ray source in the field. Redshift quoted in Allen et al.(1992), MNRAS, 259,  67.
PLCKESZ G085.99+26.71, Possible contamination by dust emission could affect Y estimate. Redshift quoted in David et al.(1999), ApJ, 519, 533.
PLCKESZ G086.45+15.29, In ERCSC at 353 GHz.     
PLCKESZ G094.01+27.42, Redshift quoted in Schneider et al.(1992), AJ, 103, 1047. 
PLCKESZ G096.87+24.21, X-ray source in the field. Possible contamination by source emission could affect Y estimate. No redshift quoted.
PLCKESZ G097.73+38.11, In ERCSC at 353 GHz.  
PLCKESZ G115.71+17.52, Candidate new cluster. BSC-RASS in the field. Possible contamination by dust emission could affect Y estimate. 
PLCKESZ G121.11+57.01, Candidate new cluster. FSC/BSC-RASS source in the field. Possible association with WHL J125933.4+600409 from Wen et al. (2009). Quoted redshift from Wen et al. (2009), ApJS, 183, 197. 
PLCKESZ G125.58-64.14, In ERCSC at 30 GHz. 
PLCKESZ G139.59+24.18, Candidate new cluster confirmed by AMI observations and possibly confirmed by WISE (details can be found in Planck Collaboration (2011j)). 
PLCKESZ G157.43+30.33, Identification from SIMBAD. Cluster quoted in Appenzeller et al.(1998), ApJS, 117, 319.
PLCKESZ G164.61+46.38, X-ray source in the field. Possible contamination by source emission could affect Y estimate. No redshift quoted.
PLCKESZ G171.94-40.65, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k). 
PLCKESZ G189.84-37.24, Candidate new cluster, low reliability. No X-ray source in the field. High level of contamination by Galactic emission.
PLCKESZ G225.92-19.99, Candidate new cluster. BSC-RASS and FSC-RASS sources in the field. In XMM-Newton and HST observation logs. 
PLCKESZ G228.49+53.12, Possible contamination by source emission could affect Y estimate. NVSS source in the field with flux 0.133 Jy emitting up to 100 GHz. 
PLCKESZ G239.28-25.99, Indicative redshift quoted in Cavagnolo et al.(2008), ApJ, 682, 821.
PLCKESZ G241.85+51.53, Possible contamination by source emission could affect Y estimate. NVSS source with flux 0.159 Jy in the field emitting up to 143 GHz. 
PLCKESZ G246.52-26.05, In ERCSC at 30 GHz.
PLCKESZ G250.90-36.25, Possible contamination by dust emission could affect Y estimate.
PLCKESZ G255.62-46.16, Candidate new cluster. FSC-RASS source in the field. In ESO and Suzaku observation logs.  
PLCKESZ G262.25-35.36, In ERCSC at 353 GHz.      
PLCKESZ G262.71-40.91, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k). Also an ACT cluster with redshift quoted in Menanteau et al.(2010), arXiv:1006.5126
PLCKESZ G264.41+19.48, Candidate new cluster. BSC-RASS source in the field. 
PLCKESZ G266.03-21.25, In ERCSC at 353 GHz. 
PLCKESZ G269.51+26.42, Possible contamination by source emission could affect Y estimate. 
PLCKESZ G271.19-30.96, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k).
PLCKESZ G271.50-56.55, Redshift quoted in Edge et al.(1994), A&A, 289, L34.
PLCKESZ G275.21+43.92, Possible contamination by source emission could affect Y estimate. NVSS source with flux density of 1.32 Jy in the field emitting in all LFI and HFI channels.
PLCKESZ G277.75-51.73, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k).
PLCKESZ G283.16-22.93, Candidate new cluster. FSC-RASS source in the field.
PLCKESZ G284.99-23.70, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k). 
PLCKESZ G285.63-17.24, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k).
PLCKESZ G286.58-31.25, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k). 
PLCKESZ G286.99+32.91, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k). 
PLCKESZ G292.51+21.98, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k).
PLCKESZ G294.66-37.02, Possible contamination by dust emission could affect Y estimate.
PLCKESZ G304.84-41.42, Candidate new cluster. BSC-RASS source in the field. In ESO observation logs.
PLCKESZ G308.32-20.23, Candidate new cluster confirmed by XMM-Newton observations. Details, including redshift estimate, can be found in Planck Collaboration (2011k).
PLCKESZ G337.09-25.97, Candidate new cluster confirmed by XMM-Newton observations. Found to be a double cluster. Details, including redshift estimate, can be found in  Planck Collaboration (2011k).
PLCKESZ G345.40-39.34, Redshift quoted in den Hartog & Katgert (1996), MNRAS, 279, 349.