SIMBAD references

We have undertaken an analysis of observed aspect ratios for the collimation disks in bipolar nebulae (BPNe). We find, as a result, that most such structures are likely to have a ratio of thickness to diameter b/a∼0.23. Similarly, the paucity of disks having aspect ratios ≥0.7 implies that many of the sources are either unobserved or, what is more probably the case, misidentified. It seems likely, as a result, that the true population of BPNe is ∼1.7 times greater than previously supposed. Similarly, we determine that as many as of 43% of annular or ringlike planetaries may represent bipolar sources oriented along the line of sight.