How to Use Asci for Obtaining Double Mutants- http://www.fgsc.net/neurosporaprotocols/How%20to%20use%20asci%20for%20obtaining%20double%20mutants%20of%20genes%20that%20show%20epistasis%20of%20are%20phenotypically%20similar.pdf
How to Use Helper Strains for Maintaining and Crossing Handicapped Recessive Mutants- http://www.fgsc.net/neurosporaprotocols/How%20to%20use%20helper%20strains%20for%20maintaining%20and%20crossing%20handicapped%20recessive%20mutants,%20for%20forcing%20and%20resolving%20heterokaryons,%20and%20for%20determining%20heterokaryon%20compatibility